You can make your own sounds and music for free from any YouTube video (Just make sure they are copy write free).
1: Take the URL of any YouTube video you find and plug them into this website than hit convert: https://y2mate.nu/en-Aj2q/
2: Then take that video's audio and import it on Audacity to extract any specific part of that audio you want (You may need to download this).
3: Then import that audio onto this website for any effects or music you want to add: https://www.bandlab.com/
You might have to sign up to all these services if it is your first time using them, but I promise they are all completely FREE and will help you create any sound you want to make from scratch. You will never have to use premade sounds.
P.S. After hitting convert on the first step, there might be another window that pops up in your browser. Don't worry about this. Just hit close on that link then proceed to your downloads.