I am not how many people know this..
Angelica Jones aka Firestar was a super-hero creasted for specifically for the cartoon series.
Her popularity led the people at Marvel to find a way to bring her into the Marvel Universe.
Surprisingly she is mentioned a lot at conventions and considered a sort of "con-cult hero", this popularity seems to have never taken her past being a filler character in stories and teams.
Many have expected her to make a re-appearance following the events of Civil War, however the only place she has been rumored to be connected is with the newset revamp of the New Warriors.