Don't know if this is still being updated, but I'd suggest Chel, from the Road to El Dorado, as a medium addition.
Scarlet Witch (with Quicksilver), Dagger (with Cloak, 2013 Ultimate editions), Stahma Tarr
Chosen, In Planning:
Red (with Subject Unknown), Evie & Jacob (Lady and Duke outfits)
Ravager, Braum (with Illaoi)