I'm really digging the Giff and the Abashai.
I'd love to see Mordenkainen's Tome of Foes include some decent Player Options like Giff, Githyanki, Githzerai, Duergar, Eladrin, and Genasi as playable races, Artificer and Mystic as Classes, and more goodies for player options (feats, spells, etc.). Maybe even a subclass or two? I know this is supposed to be primarily lore and monsters but I would love more player options sprinkled throughout. At the very least give me playable Giff and Duergar.
Sorry for the rant.