Been collecting stuff for years.. 3D models, sprites, audio, textures, and these are the places I keep going back to. Tried to include the pros and cons of each since not all "free" is created equal.

https://assethoard.com/blog/where-to-find-free-game-assets-2...

Covers itch.io, OpenGameArt, Kenney, Poly Pizza, Freesound, and a bunch of others. Also got into the different Creative Commons licences because that trips people up (myself included).

Happy to add any I've missed if you've got favourites.