Are there other websites that function just like Derpibooru?

I would love to know, especially a Pokemon one.

Yes. Twibooru, Rainbooru, Manebooru, Ponybooru, and Ponerpics are the big ones, plus some more niche sites for specific subsets of pony content.

If you’re looking for Pokemon, the only one I know of is Furbooru, a general furry site with some Pokemon stuff mixed in.

It’s literally just Derpibooru for furries. It even has some staff overlap.

I just noticed that the original post was from 8 years ago and that OP has abandoned the site. But if anyone else has the same question, it has been answered in the two posts above.