Though it's shown in The Book of Exalted Deeds I'd love to see the Moon Dog make an appearance, along with the Grell from the second edition Monsterous Manual. Who can resist a dog with hands and a freaky looking tentacled brain that has a bird's beak?
I forgot to list the amirah from the first edition Dungeons & Dragons books. That's another I'd love to see make a return.
Cross-posted to dndfanz, dnd3e, and dnd_women.