9. Black Widow
She’s been in three Marvel movies and is about to appear in a fourth one in the Avengers: Age of Ultron. She’s starred in her own semi-superhero flick with surprising success in Lucy. I think it’s about time Scarlett Johansson appears in her own solo Black Widow movie. Her story could delve into her time with Hawkeye in Budapest as a flashback but still focus on a present day story to tie into the current MCU continuity.
Image source: Comic Vine