Free 3D models split into two groups, and the split is not about quality. It is about whether the site has one license for everything, or a different one for every file.
Knowing which group you are in tells you how much care a download needs.
#Everything here is CC0
One license, no attribution required, commercial use fine.
- Poly Haven for scanned props and environment pieces, at a quality that holds up close to the camera.
- Quaternius for low-poly packs by theme: nature, dungeon, vehicles, characters, all in a consistent style so a scene built from several packs still reads as one thing.
- Kenney for low-poly kits meant to be snapped together, plus a huge amount of everything else.
If you want to stop thinking about model licensing entirely, these three will carry a whole game. That is a genuine strategy, not a fallback.
#Check every file
- Sketchfab has an enormous amount of downloadable work under Creative Commons, per model. CC BY is common, so assume you will be crediting.
- Poly Pizza carries a large low-poly collection including the old Google Poly archive. Much of it is CC BY. The creator's name is on the page and belongs in your notes.
- OpenGameArt ranges from CC0 to share-alike to GPL, chosen per submission.
#What "royalty-free" means, and does not
Paid marketplaces describe models as royalty-free, which sounds like a license and is not. It describes the payment model: you pay once rather than per copy sold. What you may actually do is in the store's terms, which are usually per seat and usually forbid redistributing the model in a form another developer could extract and reuse.
Shipping it inside a compiled game is exactly what it is for. Putting the source file in a public repository as a portfolio piece usually is not.
#The topology question nobody mentions
A free model being free does not make it usable. Before committing to one, look at the triangle count relative to how close the camera gets, whether it has been triangulated already, whether the textures come as separate maps or baked into one, and whether the scale is sane. A scanned rock at two hundred thousand triangles is not a prop, it is a decision.
Poly Haven and Quaternius are consistent about this. Mixed-source sites are not, by nature.
#Record it before you close the tab
Whichever group you are in, the license and the creator are visible right now, on the page in front of you, and will be unrecoverable in a year when the model is one of four hundred files in a folder.
Tessera records both as the pack arrives, recognizes several of these sites well enough to fill them in itself, and holds a pack in Review rather than guessing when it cannot. Later, copying into a game writes the credits from that record.
Install Tessera, or read downloads and licenses.