Oh, I don't know about that. Working in feature film animation, studios have gargantuan model libraries from current and past projects, with a good number (over half) never used by a production but created as part of some production's world building. Plus, generative modeling has been very popular for quite a few years. I don't think getting more 3D models then they could use is a real issue for anyone serious.
These are not public datasets, but with some social engineering I bet one could get access.
I've not worked in VFX for a while, but when I did the modeling departments at multiple studios had giant libraries of completed geometries for every project they ever did, plus even larger libraries of all the pieces and parts they use as generic lego geometry whenever they need something new.
Every 3D modeler I know has their own personal libraries of things they'd made as well as their own "lego sets" of pieces and parts and generative geometry tools they use when making new things.
Now this is just a guess, but do you know anyone going through one of those video game schools? I wager the schools have big model libraries for the students as well. Hell, I bet Ringling and Sheridan (the two Harvards of Animation) have colossally sized model libraries for use by their students. Contact them.
