The only official D&D class that is not currently in the game is Artificer. There are something like a hundred official subclasses though.
As for races, as mentioned, some would be easy in terms of graphics are already in: Aasimar, Githzeri, Eladrin. Bugbear would be attractive for optimisers. Thri-kreen so the animators hate you. And Plasmoid for the sex.
