I'm really hoping we get Duergar and deep gnomes as well, since, from an implementation point of view, it's just some different skin colors on existing models. Duergar get enlarge person which is a lot of fun. 8 foot tall dwarf fighter once a day.
I would say that gnomes are doubtful due to the tadpole unable to turn a gnome into a mindflayer, the process fails though it should be noted that with the addition of outside interference like dark magic they can become something else like a Gnome ceremorph, Gnome squidling or Mozgriken
