Artist tools
A tool for artist to sort their post, each artist would of course have to be pre-approved for this.
Some features would be to arrange art, places in specific folders, i.e scraps and delete post easier with one click rather than request a takedown.
I mean as an artist it can be annoying to see my older stuff posted that I know isn't as good but I don't want it to be taken down, rather just placed off somewhere else so it doesn't clog my "gallery" you know? I know some artist that rather be put on the DNP list just because of this. It is frustrating. I really just wanna emphasize the folder option, as it would allow art to still be there but off to the side not directly shown in their main gallery.
And I do not mean pools either, completely different.

This is a booru, not a gallery.

While Ratte is right, you could always use sets. Some people may not usually look at the sets a post is included in, but it's the closest to "folders" you'll have on a booru.