First off, a thing about Black Widow in Captain America: The Winter Soldier.
'Captain America: The Winter Soldier proves Black Widow is ready to go solo':
I haven't seen the movie yet, but this article made me want to post this list of female characters I hope to see in significant roles in future movies...
Her current codename is Spectrum, but she's had many of them including Photon, Pulsar, and Captain Marvel. Her power is that she can turn into just about any form of energy on the electromagnetic spectrum. (In the most recent Mighty Avengers, she
turned into gamma radiation, for example.)
Carol Danvers, former Air Force pilot, got caught in the explosion of a Kree device called the Psyche-Magnetron. It melded her genetic material (or something) with the first Captain Marvel (Mar-Vell) and turned her part Kree. Now she has the powers of super strength, flight, and energy absorption/projection, among other things.
I'm not sure which of Jessica Drew's origins is canon. It's either something about irradiated spider blood and a genetic accelerator or something about lasers with spider DNA. Whatever it was, it granted her the powers of super strength and flight. She also has "venom blasts" and can produce fear-inducing pheromone.
(She's not affiliated with Spider-Man. The Ultimate Universe Jessica Drew is his clone, but the main continuity version is...not affiliated, like I said.)
Jennifer Walters is an attorney who was shot by goons of a crime boss. Her cousin, Bruce Banner aka the Hulk, was in town and offered his blood when the hospital ran out of her type for a transfusion. The transfusion gave her Hulk abilities of her
own...because superhero comics.
When Janet van Dyne's father was killed by an alien being, Janet van Dyne wanted revenge. She turned to Hank Pym, a colleague of her dad's, who imbued her with "Pym particles". They gave her the abilities to change her size, fly, and telepathically control insects.
I have no idea if she'll feature in the Ant-Man movie. The first Avengers movie was initially more "Wasp-y" (in Whedon's words.)