You need to prototype a level? With a grid modular system based?
For a FPS game like Portal? A top-down game? A cinematic?

This product is a full interior modular Scifi PBR kit.  Due to the Unity datas sources, you will need to recreate prefabs and material in your own engine...

Note for Unreal users: When you import FBX, put a 100% Scale in the import window option, to get the Unreal Grid. for GODOT? I dont know, maybe it's like Unity?

The pack contains :
-  100 high quality png textures  (Diffuse / Normal / Ao / Metal).
- 125 FBX Files.

https://blackcreepycat.itch.io/3d-scifi-starter-kit-free

Pictures are from Unity Engine :

Free Pack License:
- For commercial or personal use.
- It can be used and edit freely. 
- Not redistribute or resell this assets. 
- It can be used for game development and other productions.

Paid Pack License:
- For commercial or personal use. 
- It can be used and edit freely. 
- Not redistribute or resell this assets. 
- It can be used for game development and other productions.