Aliens, mutants, or magic-users might all share a common set of power facts. Your campaign can have rules like "all mutants have the ability to sense other mutants", for example. GMs can write these power facts ahead of time, or borrow them from players who want to introduce a new class of super.
A character's aspect should spell out what sort of origin justifies these racial or common powers, such as "talking dog from Betelgeuse" or "wise-cracking mutant from Jersey".