6. Franklin Richards
Fox owns the film rights to the X-Men and to the Fantastic Four. There has been talk of combining the two teams into one cinematic universe. Days of Future Past provides the perfect opportunity to do this through Franklin Richards. Franklin Richards is the child of Reed and Sue Richards, also known as Mr Fantastic and Invisible Woman of the Fantastic Four. Franklin is one of the few survivors in the Days of Future Past timeline. He is also an item with Rachael Summers. Franklin is an extremely powerful mutant, with the ability to manipulate reality on a cosmic scale. In the original story, Franklin does very little, but his role could easily be expanded. He could potentially assist the X-Men in navigating the Baxter Building. There is huge potential for how Franklin could be used in the film.