Dwarf mating.
More like 'gross' or 'disturbing' to most humans, I suppose.
But eh, let's try to settle on the amount of sentient (reasonably advanced, for them) races. 3?
Anyway, you kinda ignored my other point.
Also those gnomes(And they all wear hats, to protect them from the sun) I thought of sound good.(Also get airships/zeppelins, this way)