Free Game Assets
Every asset below is free to download from its original source, and most of it is CC0, meaning you can ship it commercially without crediting anyone. These pages are browsable snapshots by category. For anything not covered here, the live asset library searches all of these sources at once, plus Sketchfab and a few others.
3D models
Textures
Sound effects
HDRIs
Sprites
How this fits together
Finding the asset is the easy part. Getting it into a game is where projects stall, so the tools that do the next step run in your browser and cost nothing: convert FBX or OBJ to GLB, inspect a model, optimize it for the web, compress textures to KTX2, rig a character, and add animation.
If you'd rather skip the pipeline entirely, describe a game and build it in the browser. The asset library is wired into it, so you can ask for a knight and get one placed in your scene.
For background on licences, sources, and what to watch for, start with the complete guide to free game assets, the best free 3D model sites, and free 2D sprites and tilesets.