Indiciate models you've already downloaded

It's hard to tell if you've downloaded a model sometimes, especially if it's similar to someone else's model for a character you already have models of. I would suggest either graying out the model to indicate it was visited or add some indication next to the download button.

It shouldn't be hard to implement since you guys already have a separate tracker page that lists our downloads, so the backend server stuff is already there to implement this.

You might want to put site suggestions and ideas in the Canny page. They won't likely get much attention here since this is a Q&A forum. There's an 'Ideas' button at the bottom right of the page, if you click that it should take you to Canny where you can suggest ideas, read the current progress, and look at other people's suggestions.

There is a "Download History" in the menu when you click on your profile picture.
Edit: Oh my bad, this is what I get for answering before reading the last sentence in your post.