I really got a chance today to dig into Monte Cook's Numenera Playtest. While the "classes" are cool the rest of the game is brilliant.
I'm hoping to do something with it soon and that has led me to brainstorm for it.
Since the game is set a billion years in the future, I feel fairly certain that anything and the kitchen sink will work for it.
Nazis or their equivalent (HYDRA, anyone?)with trained velociraptors
Nucleus, the City on the Pacific Rim
Gate, a small town in trouble
Thundarr's Broken Moon
Kremlin the Hutt
IG "assassin units"