4. Whirlwind
Whirlwind (David Cannon) mostly encountered Hank Pym in his giant form, but no one has said that a movie with Pym as the star won't explore that side of his particle experimentation as well as the tiny side. Whirlwind (who has also used the alias "Human Top") is a mutant who discovered at an early age that he could move at great speeds. He chose to take advantage of this ability by turning to a life of crime. He became a jewel thief and was stopped on a number of occasions by Pym (as Giant Man) and his partner Wasp. As a result of being constantly thwarted by the pair, he joined the Masters of Evil in an attempt to take down the entire Avengers roster. Whirlwind could, therefore, also be use as an unlikely way of introducing a live action Masters of Evil team (which would, of course, be amazing).