These questions are related to Royalty Free license, since the CC0 license technically allows you to do anything with the assets.
We however recommend you to always appreciate the authors of any creations and not to sell them anywhere, it just makes you a bad name in the 3D community.

Can I sell renders and animations made with BlenderKit?
Yes, you can.

Can I sell games made with BlenderKit models?
Yes, if these can't be extracted by the users in an easy way.

Can I sell 3D scenes made from BlenderKit models on other 3D model marketplaces?
No you can't.