Poly from Google. A WebGL-enabled search-engine for (very) low-poly 3D models for your AR/VR games, all seemingly under CC-BY. The downloads I tried were .OBJ, and some also had .FBX versions (which may perhaps indicate rigged skeletons under the surface polys, enabling animation). A Google Search site: search suggests there are around 1,200 models at present.

Looks like Google has cleaned out most of the fan-art from the launch content, but videogame makers are still going to have to check anything that looks especially ‘Disney quality’. Disney is not likely to be happy if you use their Moana boat and islands in your Google Play game…

Alternative: Yobi3D.