What’s a good website or vendor to buy books with custom-made book covers or one-of-a-kind book covers or “special” book covers?

I mean, book covers for books, especially more famous books, that have a neat or rare book cover or book cover by a different artist.

Not sure how to describe what I'm getting at. I mean, I heard that on Etsy, you can find a lot of these for famous or vintage books in particular. I'm trying to see if there's any way I can find new editions of certain books or certain book covers that are rare or by independent artists, for example.

Thanks in advance!