Croatoa enemies have a big variety of spectacular attacks that are really reskins of powers already in the game. I propose this: On completion of the defeat 333 of each faction badges you are rewarded with the following:
Firbolg: Pumpkin fire blasts (Pumpkin head is from a halloween event and not included in this) for fire blasting power sets.
Tuatha de Dannon: Hurl Roots. Like Hurl, and Hurl Boulder lifting heavy things and throwing them shouldn't be just limited to rocks.
The Cabal: Cloudy Lightning for lightning power sets
Ghosts: Ghastly Dark Blasts. Blast your enemies with the souls of the damned! (also possible for the aoe powers in other dark sets perhaps)
Red Caps: Knives! Big knives, small knives! For all the stabby sets (Broadsword, Katana, Dual Blades and adjoining sets.)