>>47367992"Aura forms" that can directly adjust base stats (either by taking points from one stat and dumping them in another, or just outright making it 80 or something). It also gives a Pokemon usage of all abilities that they can normally have (with some exceptions if it'd be too broken or self-defeating) and/or an all new super-powered ability. It only lasts one turn, but you get 5 opportunities to use it over the course of the battle for your entire team.
That's too specific to ever be right, but abilities haven't really had any focus as gimmick so I just shat something out that could give them a spotlight.