Lets start off with a funny system similar to TH14.3 where you upgrade cheat items by playing the game.

All of the items presented here can be upgraded when you win in battles of higher CR than your party level. Uncommon for acquiring the item, Rare for 3 battles, Very rare for 10 battles and legendary for 20 battles. (that's just a rough idea of what I think it should be.)

Alternatively a better system would be to calculate the CR difference of the party and the battle. Already then use that number as the progress towards the magic item upgrade.

For example, in a battle where you face CR 13 monster as a level 5 party, if by any miracle you win, you get 8 points towards your magic item progression. A good motivation to challenge gods as a training to get stronger.

The items shouldn't require too many battles to upgrade otherwise accidental wins over a stronger foe won't be as rewarding. So I suggest something like this:

Table of "CR points" gathering

CR | points

Same CR | 1 point

CR higher by 1 | 2 points

CR higher by 2 | 3 points

and so on by formula of (CR of encounter - Party level + 1). (You also gain double points if you don't use any magic items during this battle, let's say, if you can beat the impossible spell cards without cheat items, they weren't that impossible! Could be an optional rule)

Now, Table for upgrading cheat magic items.

Rarity transfer | Points required

Uncommon to Rare | 10 points

Rare to Very Rare | 20 points

Very rare to legendary | 60 points

(There are no common rarity here by the way, and items are crafted in uncommon version only. Also by the way, after reaching a new rarity, the progress bar doesn't reset but keeps on going. This is needed for some specific situation.) 

Also, in front of all items, there should be this message ->"This item absorbs your struggles and becomes stronger with you. To upgrade this Magic Item you need to win in a battle CR of which is higher than your level." to be similar to "dragon wrath weapon" magic item description from official DnD

Nimble Cloth

Wonderous item, rarity varies, (attunement required).

Purple-blue checker pattern piece of fabric which under certain angles looks blurry. If you stand still and use it to cover yourself, you'll be invulnerable for a short while.

Miss Nimble (uncommon): 2 charges, expend 1 charge and an action to hide on the other level of plane until your next turn, you are thrown out of it afterwards which wastes your bonus action and 10 feet of movement. Use it to "evade flutteringly~" any deadly attacks.

Nimble-ster (rare): 3 charges, expend 1 charge and an action to hide on the other level of plane until your next turn. You are thrown out of it afterwards which wastes 10 feet of your movement. "Does dodging so neatly make you look like a matador?"

Nimble Master (very rare): 4 charges, expend 1 charge and an action to hide on the other level of plane until your next turn, alternatively expend 2 charges and a bonus action to hide on the other level of plane until your next turn. You are thrown out of it afterwards which wastes 10 feet of your movement. "I wonder how it feels when danmaku flies over the cloth".

Nimble Space God (legendary): 5 charges, expend 1 charge as an action to hide on the other level of plane until your next turn. Alternatively expend 2 charges and a bonus action to hide on the other level of plane until your next turn. Alternatively expend 3 charges as a reaction to hide on the other level of plane until your next turn. You are thrown out of it afterwards which wastes 10 feet of your movement. "I've become the god of Nimble Space".

All charges are restored at dawn.

(Good enough in my opinion. Didn't use this item that often, but I think it works just right. A more reliable dodge with a drawback of movement and little amount of charges. Takes a while for it to actually become good.)

Tengu Toy Camera

Wonderous item, rarity varies, (attunement required).

Toy camera made out of plastic. It can create a very bright flash capable of blinding your enemies, "You flash with a bang, so continue to flashbang!".

Camera Kid (uncommon): 2 charges, expend 1 charge and an action to prepare using it as a reaction. When used, erases all projectiles in 20 feet cube right in front of you. If any attacks are made against you in the same round of battle after using this ability, they roll with Disadvantage. If an enemy is inside the cube of area, it must succeed on Con saving throw of DC 14 or have blinded condition until the end of the round. "You're still just a fledgling cameraman."

Camera Adult (rare): 3 charges, expend 1 charge and an action to prepare using it as a reaction. When used, erases all projectiles in 30 feet cube right in front of you. If any attacks are made against you in the same round of battle after using this ability, they roll with Disadvantage. If an enemy is inside the cube of area, it must succeed on Con saving throw of DC 16 or have blinded condition until the end of the round. While holding this camera, when using a dash action, you gain +10 feet movement total and +1 AC until the start of your next turn. "You've grown up a little! But the camera is still a toy."

Camera Gentleman (very rare): 4 charges, expend 1 charge and an action to prepare using it as a reaction. When used, erases all projectiles in 40 feet cube right in front of you. If any attacks are made against you in the same round of battle after using this ability, they roll with Disadvantage. If an enemy is inside the cube of area, it must succeed on Con saving throw of DC 18 or have blinded condition until the end of the round. Alternatively, for 2 charges you prepare to use this item as a bonus action to later use it with your reaction. While holding this camera, when using a dash action, you gain +20 feet movement total and +2 AC until the start of your next turn. "A generation of a hundred million cell phone cameramen. Let's use them in a gentlemanly way."

Camera Demon (Legendary): 5 charges, expend 1 charge and an bonus action to erase all projectiles in 50 feet cube right in front of you. If any attacks are made against you in the same round of battle after using this ability, they roll with Disadvantage. If an enemy is inside the cube of area, it must succeed on Con saving throw of DC 20 or have blinded condition until the end of the round. Alternatively, for 2 charges you prepare to use this item as a bonus action to later use it with your reaction. Or expend 3 charges to use this item as a reaction. While holding this camera, when using a dash action, you gain +20 feet movement total and +3 AC until the start of your next turn. Feel free to say "I've become a camera demon" after flash banging your foes.

All charges are restored at dawn.

(Flashbang crows builds incoming straight in! Honestly a good magic item, I hope it won't break your Tengu camera, it can't make pictures so I hope it's alright, if you hate any of my suggestions, just reduce the numbers here and there, (just in case, charges hit the viability of the item the most) overall a niche item, capable of introducing your enemies to the role of been a solo B opp in CS.)

Gap Folding Umbrella

Wonderous item, rarity varies, (attunement required).

Looks like common pink folding umbrella, and it can be used as a regular umbrella. It is rumored that it allows you to cross screen border, that's very popular talk amongst many humans and youkai, because "what is a screen edge, anyway?" it's a great topic for getting people's interest. (TH18 reference)

Closed Umbrella (uncommon): Has 2 charges, using your action and 1 charge produces an Invisible 3-foot-by-5-foot portal within 10 feet in unoccupied space, it opens to an extradimensional space that lasts until the start of your next turn.

The space can hold up to 2 Medium or smaller creatures. Attacks, spells, and other effects can’t pass into or out of the space, but creatures inside it can see through the portal. Anything inside the space drops out when the portal vanishes.

Once inside the space, select a second portal location within 30 feet. The space now has 2 exits. Effectively creating a wormhole with a small room for tea breaks for 1 turn.

Favorite Umbrella (rare): Has 3 charges, using your action and 1 charge produces an Invisible 3-foot-by-5-foot portal within 10 feet in unoccupied space, it opens to an extradimensional space that lasts until the start of your next turn.

The space can hold up to 2 Medium or smaller creatures. Attacks, spells, and other effects can’t pass into or out of the space, but creatures inside it can see through the portal. Anything inside the space drops out when the portal vanishes.

Once inside the space, select a second portal location within 60 feet. The space now has 2 exits. Effectively creating a wormhole with a small room for tea breaks for 1 turn.

Alternatively, you can expend 1 charge to cast Misty Step.

Umbrella House (very rare): Has 4 charges, using your action and 1 charge produces an Invisible 3-foot-by-5-foot portal within 10 feet in unoccupied space, it opens to an extradimensional space that lasts until the start of your next turn.

The space can hold up to 4 Medium or smaller creatures. Attacks, spells, and other effects can’t pass into or out of the space, but creatures inside it can see through the portal. Anything inside the space drops out when the portal vanishes.

Once inside the space, select a second portal location within 90 feet. The space now has 2 exits. Effectively creating a wormhole with a small room for tea breaks for 1 turn.

Alternatively, you can expend 1 charge to cast Misty Step.

Umbrella Paradise (legendary): Has 5 charges, using your action and 1 charge produces an Invisible 3-foot-by-5-foot portal within 10 feet in unoccupied space, it opens to an extradimensional space that lasts until the start of your next turn.

The space can hold up to 8 Medium or smaller creatures. Attacks, spells, and other effects can’t pass into or out of the space, but creatures inside it can see through the portal. Anything inside the space drops out when the portal vanishes.

Once inside the space, select a second portal location within 120 feet. The space now has 2 exits. Effectively creating a wormhole with a small room for tea breaks for 1 turn.

Alternatively, you can expend 1 charge to cast Misty Step.

Restores all charges at dawn.

(A mix of rope trick and misty step, not as powerful as others, but it can be used to utility cast, like make Portal particle accelerator for 6 second. And remember! This one is broken not because I made it, but because Wizard of the Coast invented rope trick, wording of which I used! Hohoho, also I reduced duration and space of the rope trick cuz that's too powerful even to my standards. So, stat wise this is not as strong as rope trick.)

Ghastly Send-Off Lantern

Wonderous item, rarity varies, (attunement required).

A paper lantern with symbolic writing on it, it helps ghosts to find their way to the world of dead. However this has done it's job so well that it started accumulating fraction of magic from all passing ghosts, thus starting to behave like a magic item. If one is to unseal it's accumulated magic, the user will be saturated with otherworldly magic forcing him to change into the "Phantom state". This state makes you constantly shift through the planes which practically makes the user invulnerable while still allowing to interact with anything like usual.

Miss Passing Ghost (Uncommon): 1 charge, expend a charge as an action to enter "Phantom state" for 2 turns. In this state you can't be targeted by an attack and you don't receive any damage. You are still capable of interacting with the world around you, including object interactions, attacks and casting spells. After 2 turns, you are dropped out of "Phantom state".

"You don't have a lot of presence, huh?"

Perhaps a Vengeful Spirit? (Rare): 

1 charge, expend a charge as an action to enter "Phantom state" for 2 turns. In this state you can't be targeted by an attack and you don't receive any damage. You are still capable of interacting with the world around you, including object interactions, attacks and casting spells. Additionally, you gain + 5 feet of movement and +1 to all attack rolls. After 2 turns, you are dropped out of "Phantom state".

"Being a ghost seems like more fun, huh?"

Splendid Spirit Body (Very rare): 

1 charge, expend a charge as an action to enter "Phantom state" for 3 turns. In this state you can't be targeted by an attack and you don't receive any damage. You are still capable of interacting with the world around you, including object interactions, attacks and casting spells. Additionally, you gain +10 feet of movement and +2 to all attack rolls as well as you can remove 1 of the following conditions from yourself: Blinded, Deafened, or Poisoned. After 3 turns, you are dropped out of "Phantom state".

"I'd love to have a spirit body...

My back and shoulders have been hurting lately..."

A Born Ghost (Legendary): 

1 charge, expend a charge as an action to enter "Phantom state" for 3 turns. In this state you can't be targeted by an attack and you don't receive any damage. You are still capable of interacting with the world around you, including object interactions, attacks and casting spells. Additionally, you gain + 15 feet of movement and +3 to all attack rolls as well as you can remove 1 of the following conditions from yourself: Blinded, Deafened, or Poisoned. After 3 turns, you are dropped out of "Phantom state". You also gain the power to use this item if it has any charges left as a reaction if you were to be reduced to 0 HP by any means.

You can now freely say "I've become a born ghost".

Restores all charges at dawn.

Curse: after using this magic item you are Incapacitated and have a Speed of 0 until the end of your next turn, as a wave of lethargy washes over you especially after passing beyond the border of life.

(This item seems strong, but I think if we put it in levels, then it's alright. Because a single invincible player even on multiple turns can't alone kill an enemy of his own CR or higher. Plus it's a single use per day item, thus it will only be used in situation close to death. Which means player will use it very rarely. Maybe if it seems too powerful, add more to the curse, like every turn in phantom state drains your health or after exiting it you have WAY more penalties. But I think it's not necessary, it is already not the best item due to a single charge it has. I also put it's sub-item effect to legendary tier just because, I have no idea how to balance it. So I'll just leave it there as a good final upgrade to this item many people won't see. Also, imagine the eyes of the player when he uses this item and later it is revealed that now his character is a vegetable for an entire round! Now that's some good comedy! Especially if it is an air fight. Also, maybe give some ghosts features to the phantom state, like hovering and passing through walls.)

Bloodthirsty Yin-Yang Orb

(Does anyone even use this item?)

Wonderous item, rarity varies, (requires attunement).

Appearance of this ball is extremely similar to the Hakurei holy Ying Yang orb, however this one has colors of real blood on it as well as unique magic which allows it's user to teleport right in front of their foe to smack them with all their force. It is told that this orb is capable of benefiting the development of bloodlust in it's user.

Ball User (uncommon): has 4 charges, as a bonus action and 1 charge immediately teleports user to a foe in 30 feet range. Additionally, it gives you a free weapon/unarmed attack against a foe you teleported to. Alternatively, you expend 2 charges and an action to use this item. In this case, any attacks rolls against you, are made with Disadvantage and you make Dexterity saving throws with advantage until the start of your next turn. If you are attacked during this period of time, you can immediately teleport to within 5 feet of the attacker if they are in 30 feet range of you, once in front of them you gain a free weapon/unarmed attack against them.

"Popping out right in front of the boss's face feels nice..."

Ball Craftsman (rare): has 5 charges, as a bonus action and 1 charge immediately teleports user to a foe in 60 feet range. Additionally, it gives you a free weapon/unarmed attack against a foe you teleported to. Alternatively, you expend 2 charges and an action to use this item. In this case, any attacks rolls against you, are made with Disadvantage and you make Dexterity saving throws with advantage until the start of your next turn. If you are attacked during this period of time, you can immediately teleport to within 5 feet of the attacker if they are in 60 feet range of you, once in front of them you gain a free weapon/unarmed attack against them.

This Orb somehow makes your bloodlust stronger, thus making you able to dodge just if you were a little smaller. Gives +1 AC.

"There's a theory that the ball and the protagonist have the same weight."

Ball Hermit (very rare):has 6 charges, as a bonus action and 1 charge immediately teleports user to a foe in 90 feet range. Additionally, it gives you a free weapon/unarmed attack against a foe you teleported to. Alternatively, you expend 2 charges and an action to use this item. In this case, any attacks rolls against you, are made with Disadvantage and you make Dexterity saving throws with advantage until the start of your next turn. If you are attacked during this period of time, you can immediately teleport to within 5 feet of the attacker if they are in 90 feet range of you, once in front of them you gain a free weapon/unarmed attack against them.

This Orb somehow makes your bloodlust stronger, thus making you able to dodge just if you were a little smaller. Gives +2 AC.

"The yin-yang orb has kind of a flat design, huh?

I wonder what would happen if you split it."

Co-egg-cidental Tester (legendary):has 7 charges, as a bonus action and 1 charge immediately teleports user to a foe in 120 feet range. Additionally, it gives you a free weapon/unarmed attack against a foe you teleported to. Alternatively, you expend 2 charges and an action to use this item. In this case, any attacks rolls against you, are made with Disadvantage and you make Dexterity saving throws with advantage until the start of your next turn. If you are attacked during this period of time, you can immediately teleport to within 5 feet of the attacker if they are in 120 feet range of you, once in front of them you gain a free weapon/unarmed attack against them.

This Orb somehow makes your bloodlust stronger, thus making you able to dodge just if you were a little smaller. Gives +3 AC.

"Co-egg-cidentally, I'm a Co-egg-cidental Tester"

Restores all charges at dawn.

(Lame item for lame people, but it has good dodging capabilities for fighters open to receive a lot of opportunity attacks in a face if they use it too much. Second way to use this item is literally just Dodge action with a funny twist. I dunno, all those items balancing is all over the place! My head hurts from thinking so much! I had to rework this item 3 times before I was satisfied, because nullifying ranged attacks and getting opportunity attacks from them was too strong, 10 charges with multiple attacks goes the same way, however now I am a little more satisfied, you can't spam dodge with this item due to limited uses and the passive ability is not as good as upcasted shield of faith spell on it's respective level of obtainment!)

Wondorous item, rare. (Consumable)

Pot with a symbol of sunflower on it.

If you plant an ordinary sunflower seed in this 10-pound clay pot and let it grow for 30 days, the sunflower magically transforms into a Dancing Sunflower at the end of that time. It's roots break the pot, destroying it. After that, it must be planted in the soil or another pot.

The Dancing Sunflower is Friendly toward you and obeys your commands. Absent commands from you, it does nothing.

The sunflower has two big black eyes and a big smile on it's face of sunflower seeds. It waves left and right constantly, imitating a dance, hence getting it's name of a Dancing Sunflower.

The Dancing Sunflower has 20 HP and 13 AC. As an action,  it can use Conjure Plants and use True Sunflower. To recharge a single ability the Dancing Sunflower must wait a day and have access to sunlight (doesn't need it when casting).

Conjure Plants: Conjure fairy spirits that appear as plants in unoccupied spaces that you can see within 60 feet range. Choose one of the following options for what they become:

1 plant of CR 2, 2 plants of CR 1, 4 plants of CR 1/2, 8 plants of CR 1/4.

Each plant is considered a fairy, they disappear when they drop to 0 HP or after 1 hour has passed.

The summoned creatures are friendly to you and your companions. As well as obey all your commands.

True Sunflower: For 1 minute, the Dancing Sunflower glows with bright light in the range of 60 feet and additional 30 feet of dim light. This light is considered a sunlight. Any creature within this area of light has resistance to necrotic damage. (This is a level 4 equivalent spell so normal Darkness spell doesn't work on it)

(Yuuka gameplay magic item, turn this silly turn based TTRPG into some good old PvZ! I could replace Conjure Plants ability with something else, for example, proper conjuration of Pea-shooters and Wall-nuts but that would be too far from Touhou. So, I'll let it slide in this form. Additionally, this funny sunflower casts Level 4 equivalent spells once a day, like level 4 conjuration of something and powerful light spell capable of buffing allies and potentially hurting some vampires. Got those 2 spells inspiration from here: https://www.5esrd.com/spellcasting/3pp-spells/loremasters-archives-of-wonder-pub... and https://www.5esrd.com/database/spell/conjure-plants/)

(This isn't a Touhou item really, just some funny midnight inspiration inspired by Touhou PvZ collab fan art where Yuuka waters PvZ sunflowers.)
(Changelog 1.1, changed it to Rare due to sudden realization that level 4 spell creating potential army of summons is probably more powerful than uncommon consumable should provide. Due to that also increased Sunflower HP from 10 to 20 and AC from 11 to 13, it's dancing, so it should be hard to hit with all that dancing. Plus dancing strengthens your muscles... or plant fibers? Either way, proper change to stats, yeah I quadruple the price for this thing, I feel bad about it, but it makes up for it in the right hands I guess. Maybe adding another spell to the list of this sunflower will make it more balanced. Perhaps it will be something to do with singing, like motivational speech or aid. Would be nice support/healer.)

Ice Fairy Plushie

Wonderous item, rare, (require attunement)

This marketable plushie has not only the appearance but also Cirno's ability to scatter ice shards everywhere.

Once a turn, you can use free action to shoot 120 feet of cone, which deals 2d8 cold damage, on the successful dexterity saving throw, the damage is halved.

"Attacking wildly in every direction is far too thoughtless.

But for an ice fairy, that's exactly what proves that she's the strongest around!"

(Similar to the rare magic item which deals additional 3d6 fire damage but instead of melee, it is long ranged AoE, that's why I reduce the damage so much. Still a pretty strong item capable of oneshotting low-tier faires if you get VERY lucky. I wonder what will happen to Cirno if she gets this plushie and Legendary Chirumiru... Maybe she will get stats from Skardae's Cirno which has CR of 11)

Lucky Rabbit's Foot

Wonderous item, common.

Lucky charm made out of rabbits floof which they occasionally naturally drop. masterfully weaved and attached to red rope making it an excellent key charm!

Has 1 charge. As a free action for 1 charge, you can make an additional roll with the dice to any roll and choose the one with the highest value.

Recharges a single charge at dawn.

(Inverse silvery barbs? Isn't that strong? Well, nah, in an adventuring day, there is a lot of bad things that can happen to you. Thus, turning disadvantage into super advantage seems good enough to save your ass in death situation once a day. Also, considering a single use of this charm, player will never use it thinking that later it will be better to use than now, thus, making him never use it. Thus, not that strong in the real scenario)

Sutra of Dharmatic Power

Wonderous item, rare, (requires attunement).

Magical sutra containing Byakuren Hijiri's ability to massively buff your Spells and "reduce their cooldown".

Counts as an arcane focus, gives +1 to attack rolls with spells.

Has 7 charges, when you can a spell, you can expend the single charge to deal additional 2d6 of damage type same as the spell, you can spend up to 3 charges at a time, each additional charge increases the damage by 1d6. If the spell has a saving throw which halves the damage. The additional damage dealt by this magic item is applied after the initial halving.

Additionally, you can expend 1 charge to remove the "1 leveled spell per turn rule" as a free action for a single turn. Thus, allowing you to use leveled spells in both your action and bonus action.

"You can attack enemies with your peashooter all you like, but in the end, you're bound to get cornered in no time and beat 'em with a huge release of magic. So if you're gonna power something up, it's gotta be your most powerful Spellcard!"

(Okay, this item might be very strong, but it has limited charges which makes it more controllable for a DM. However, I would say that players might only use the ability which allows them to cast leveled spells as an action and bonus action. For those players, I think that after the first use of that ability, we can make it take 2 charges. For balancing purposes of course. Also, this isn't an artifact because Byukaren made it while sealed in the Makai from scrap alike Tony Stark. So a wealthy adventurer who can put 2000 GP for good materials and spend 50 days of crafting. Then he would probably be able to make something of alike. Although it is probably way weaker than Byukaren actual Sutra)

Gale Geta

Wonderous item, uncommon, (requires attunement)

Special (Shoes?) worn by the great tengu which allowed them to move at record speeds. They have a fraction of Aya Shameimaru's ability to have super-fast movement.

"You can move at extreme speeds while not firing any shots.

During high-speed movement, your hitbox becomes extremely small. It's the ability to cause hitbox crimes that only a tengu can do."

You get +2 AC, +30 feet of movement (Flying or running) and you don't provoke opportunity attacks. However, to use those benefits you can't attack or cast spells affecting enemies that turn. If you do attack an enemy in any way, you won't be able to use any of the listed ability in that round of battle (you can't just move +30 feet and then attack, that's not how it works).

(Cool item, I bet that with this item, Tengu can cross the entire Gensokyo in mere minutes. Because movement of 750 feet a minute, seems pretty fast. That's not including dash. We better start thinking about theoretical impact damage of tengu going full speed and hitting a pedestrian fairy who accidently got in a way!)

Princess Kaguya Secret Stash

wonderous item, uncommon, (requires attunement)

"A box containing Kaguya Houraisan's ability to produce a Spell Card whenever you get hit."

When you get hit and receive damage (can't be friendly fire), you recharge a single spell slot of (spell caster level divided by 3 and rounded up, can't be lower than 1) level. If you are full of spell slots for that level, you either don't get anything, or you recharge a spell slot of lower levels (you still get nothing if they are also full).

"Nobody needs impractical things like five secret treasures.

What do you think the most crucial thing for an eternal life is?

...That's right. Savings."

(Spell slots are important, but taking damage for squishy casters is probably a bad idea. Thus rarity is so low. And with bigger caster level, the monsters will get more damaging, thus taking even a single hit with your face might be a bad thing. Unless you are half caster, to who this ability might be a very useful ability! That explains why this weak item requires attunement.)

Amulet of the Best Lawyer in Hell

wonderous item, Rare, (requires attunement)

"Eiki Shiki, Yamaxanadu's ability to spend 200 of your GP and pretend that a death has never happened. I know everything that you did in life before you died. ...Since you have that much money in your possession, it seems that you're worthy enough to get a second chance at life."

While attunded to this amulet, you can instantly vaporise 200 GP in your possession and pretend that you weren't hit by any attack. You double the amount of GP needed to use this ability again if used in the same battle (For example, 200, 400, 800, 1600, 3200, 6400, 12800 and so on for every hit). If you don't have enough money, then you can't use this item.

(If you are scared that your players will have bazzillion of GP, you can always change this item to double the exponent and not the number itself. For example, 200^1, 200^2, 200^3, 200^4, 200^5 and so on. But I think this is a pretty good ability. Cuz you will be broke in short adventures)

Lucky Cat statue with Good Business Skills

wonderous item, common.

"Mike Goutokuji's ability to improve product lineups.

The variety of cards you can buy from bosses will increase!"

This lucky cat statue brings fortune to whose who seek goods. Thus, when creating magic items, the "Raw Materials" supplies chance of been in your town increases from 25% in small towns and 75% in big towns suddenly jump to 100%. (You just got very lucky!)

Additionally, when you have this statue in your inventory, you gain +1 to all rolls related to trading.

(Hey, those statues might help to magic item crafters and those who like to do some business. Perfect item for Kappa. But it is EXTREMLY situational and even there, kind of weak. Thus, common. Plus it's a marketable mascot of good business, every shop owner would like to have this one. With big demand, comes nicely placed Kappa factory atop of Youkai Mountain!)

Heavy Bass Drum

Wonderous item, uncommon, (requires attunement by a bard or anyone with drums instrument proficiency)

Drum inspired by Raiko Horikawa's ability to wipe away enemy bullets at close range.

"It's plain, but you can thwack it over and over!

What do you think enemy bullets are made of?

They're waves. Ergo, there's nothing strange about

being able to cancel them out with sound waves!"

Has 10 charges.

Hitting the drum (1 charge): You can use your action to prepare to hit the drum when there will be bullets around and erase them in 10 feet radius from you. Until the start of your next turn, any attack roll against you has disadvantage and you make any saving throws with advantage. Additionally, if you do receive any damage, you can reduce it by 3d4. 

All charges are restored at dawn.

(Had to add charges because it makes you very tanky but also very inefficient if you do it every turn. Would go pretty good for bards to just use their action to be immortal and use their bonus action to heal, alternatively sorcerer with proficiency could use quickened spell with this item to be immortal fireball cannon. But its limited and there is a chance to deal damage to the player, sooooo, not that bad. Plus players hate to use their main action for something else than attacking. Although this slightly better dodge might change their mind)

That's it for today.

Surprisingly only took me 2 hours to write all those items. I could probably translate them to Russian. But I'll think about it later. For now, I will probably for a while forget about Touhou 18. Played a lot of it recently. I should return to Touhou 14.3 to make some magic items from it. Had a funny idea about them. Similar to Dragon Wrath Weapon magic item. For example, you upgrade the magic items by beating up creatures of higher CR than you. I think it's a nice way to showcase that ark of upgrading your weapon and to sew in some Touhou 14.3 achievements into it for additional points of roleplay and attachment to the item. That's why I avoided touching items that has similar effects to them.

I hope that some of my pitched ideas will be noticed and potentially review for implementation into the addon. Maybe with some rebalancing of course. Because I made those items through a lense of an artificer who are looking to make the biggest value magic item in terms of time and money to power ratio. Thus, making some of them pretty obvious choices to craft in downtime for someone like Kappa.

Potion, rare

It is a an alchemist flask with a wooden stopper which has bubbling purple liquid in it.

After drinking it as a bonus action, for 1 hour, after receiving damage, you can decrease it through equal exchange of spell slots or martial class features.

Spell slot conversion into damage reduction: You can spend as much spell slots as you want as a reaction to reduce the damage by 1d10 for every 2 combined level of spell slots, (For example, 2 spell slots of level 1 or 1 spell slot of level 2). You can upcast this effect by spending more spell slots. The same 2 levels of combined spell slots reduce damage by 1d10. If you only have a single combined level of spell slot left, you can use it as if you had 2.

Martial class features conversion into damage reduction: For monks, 1 Focus Point (Ki) you reduce 1d10 damage as a reaction. You can upcast this by spending more Focus Points in exchange for reduction of 1d10 for each Point spent. For fighters, for a single use of Second Wind, you reduce 2d10 damage, for each additional second wind you reduce damage by 2d10. For Barbarians, 1 charge of rage will reduce damage by 2d10, each additional charge of rage, it will reduce damage by additional 2d10. For Rogues, you can reduce damage by 3d10 in exchange for that you won't use sneak attack next turn.

"A medicine that's popular with demographics who have issues with elixirs of immortality, but will happily accept elixirs of long life. There's really not much difference, though."

(The balancing for this item was made via "damage by level and serenity" chart from Zee Bashew. It's a funny potion for full casters because to just not die, you have to spend big resources, the later you are in the game, the more damage you receive! So, wizards will spend a lot of their spell slots just not to die! Although balancing martials was pain in the ass, they don't really need it due to their hp reserve, but considering their low amount of resources available to them, it makes it fair. Overall a nicely balanced item for all levels in the game) (Item rework from Touhou 18, now in a potion format!)

Wondrous item, uncommon, (requires attunement)

This strange looking Unedified Fantastic Object under different angles changes it's color from red to blue to green, sometimes even all at the same time! This UFO flies around you and although distracting, it is also very distracting for your enemies!

 While attuned to it, you have resistance to force damage, and you have immunity to damage from the Magic Missle spell. You also gain a +1 bonus to AC and saving throws while this UFO circles around you.

Curse: while you are attuned to this magic item, you have -2 to passive and regular perception checks.

"The UFO becomes a shield, capable of erasing bullets. You've seen plenty of photographs of UFOs, right? But there's no space war going on. UFOs fly around just because they feel like it."

(Similar to brooch of shielding and cloak of protection but a little stronger and a little weaker at the same time. At first glance it would seem more powerful than a regular uncommon magic item due to combination of effects from 2 very strong uncommon magic items. However, the curse is also very strong! Perception is considered an S-tier skill which makes it high risk, high reward magic item.) (This is a rework of ability card from Touhou 18)

Wonderous item, Rare, (Requires attunement)

"Can shoot snake bullets that bite at the enemies." Best self defense item sold on the entire Youkai Mountain!

This amulet has 7 charges. While holding it, you can expend no more than 3 charges to cast Sylune's Viper. For 1 charge, you cast the level 3 version of the spell. You can increase the spell’s level by 1 for each additional charge you expend.'

The amulet regains 1d6 + 1 expended charges daily at dawn. If you expend the amulet's last charge, roll 1d20. On a 1, the amulet crumbles into ashes and is destroyed.

"People say that holding this charm gives you a healthier body."

(This is pretty much wand of Fireball but with a more single target approach, knowledgeable wizard will know, that this spell is on the same level as fireball in effectiveness if not better. So you better hope your players haven't paid big attention to this poison based spell ;) that's why it's rare magic item. Because it will cost 4k GP in the Moriya Shrine and 2k GP if you want to craft it. Which makes it problematic for Min-maxers to get their hands on it)

(No way, this is another magic item based on Touhou 18! I love that game!)

Wondrous item, uncommon 

"The Moriya Shrine's popular amulet."

On this amulet, there is a fat frog drawn which holds a sign saying "Stay safe!".

This amulet has 3 charges.

You gain Advantage on any navigation checks. Additionally, if you ask it to lead you home, for 1 charge spend, it will produce thin magical light string showing you the shortest direction to characters home. If character is homeless, it will lead you to your favorite spot where you often slept in the recent times.

If you spend 1 charge, it will conjure a green frog as a bonus action. You can throw it as an action for up to 60 feet, it will deal 4d6 fire damage in the 10 feet radius sphere, passing Acrobatics DC 12 saving throw halves this damage.

All charges restore at dawn.

(Very nice magic item which gives martial classes potential for ranged attacks without requiring succeeding upon an attack roll. Might be helpful if you are fighting some high AC monster like Iron Golem or something. Just on 1d6 damage more than gunpowder horn. So nothing bad. You could probably buy this amulet at the Moriya Shrine. Considering Kanako been a greedy hag, she would defiantly exploit Suwako for business purposes.)

(This is also another magic item inspired by Touhou 18 ability card. It has so many good potential items there. With very nice descriptions which are very easy to carry over to DnD! A treasure for those who wants to make a lot of magic items!)

Wondrous item, common, (requires attunement)

This hat has portion of Koishi Komeiji's ability which prevents one from crashing into enemies.

This hat makes you less noticeable to the enemies, while wearing this hat, you do not provoke any opportunity attacks.

"Is it just me, or is nobody noticing me? Huh, okay. That's convenient."

(Considering that all Tuhus rarely wear anything different, they most likely have tons and tons of same exact clothes in their homes. Especially considering that after losing a spell card battle, you can see their clothes with holes and other damages. With often battles in Gensokyo, you will of course need tons of your favorite clothes! Somebody who makes this clothes (most likely the spider lady from Touhou 11) could make some money while selling duplicates or alternatively the clothing can just be stolen by Marisa or sold by the owner. Thus, making it very likely to come upon things alike this in Gensokyo)

(Also this item is a reference to Touhou 18 ability card which nobody picks)

Potion, Rarity Varies

When you drink this potion, your Intellect score changes for 1 hour. The rarity determines the score (see the table below). The potion has no effect on you if your Intellect is equal to or greater than that score. Additionally, you get +1 to your dexterity saving throw modifier for the exact same duration.

The final product looks like milk. Usually the powder is sold in the cans through Gensokyo TV shopping. On the back side of the can it has the ingredients label which says "This product contains: Lactoferrin, Iron, Mineral, Vitamin C and Sphingomyelin"

There is also a recipe label on the side which says "Melt the ice into water. Mix the powder in and then you can drink it shortly after"

Potion, Intellect, Rarity.

Commercial Chirumiru powdered milk, 21, Uncommon

 Commercial premium edition of Chirumiru powdered milk, 23, Rare

Rare commercial super deluxe baka 9 edition Chirumiru powdered milk, 25, Rare

Fairy gang special Chirumiru powdered milk, 27, Very Rare

Special Mokou fried Cirno version of Chirumiru powdered milk, 29, Legendary

(Author comment: I practically copied the potion of giant strength page and did some minor changes, however considering Intellect been a pretty rare skill to be used. I gave it a little buff with dexterity as a reference to original Chirumiru video where it says that it enhances dodging capabilities. I also really like that legendary version of this potion will give +9 modifier to intellect which I find ridiculously funny. I also think it gives interesting roleplay capabilities, for example a dumb ice fairy could turn into professor Cirno (From Touhou monster TD) who can come up with an interesting plan or analyse the incident to assist in solveling it. After all, what's cooler than been cool? (Ice cold!!1))

Wondrous item, common, uncommon and rare.

This orb is capable of purifying the air around it and help pure land citizens to say pure. There are 3 variations of this orb. Lunarian which is made out of moon dust and rocks. Hellish which is made out of warm to touch basalt. And finally celestial which is solid but has has texture of a cloud with hint of fruity smell.

(Common) The orb can freeze pure land citizen feat timer within 5 feet for only one creature.

(Uncommon) The orb can slowly rewind a timer for pure land citizen feat within 30 feet for multiple creatures. The carrier of this orb is also immune to "inhale" type poisons (for example it can help avoid corpse poison in the air while going through catacombs). The orb can purify small quantities of water if submerged into it. (For example, it can purify potful of water).

(Rare) Anyone with pure land citizen feat who inhales a lungful of purified air in 100 feet radius gets their feat timer set to zero. Additionally, it makes everyone within this radius immune to "inhale" type poisons. It can purify small bodies of water (for example, clean an old turtle pond or clean a little area in bigger body of water). If left in the same place for an hour, it will purify the land around it and make long rests made in the area yield bonuses. For example, characters can't get ill while in range. As well as repelling any air impurities around it such as magical scarlet mist, bad odors and other bad for health conditions of air in the area. For example, purifying air in volcanic regions to avoid any lung related diseases due to inhaling ash and silica.

Depending on the type of orb. The purified water may taste differently. The celestial orb might make it taste a little fruity while hellish orb will make it taste like hot springs water. However, the differences between appearance is purely cosmetical and doesn't affect efficiency.

(This item is a reference to one of the stories in Touhou 19)