Jubilee

I have no idea what kind of role Jubilee will have in X-Men: Apocalypse. However, she is one of the most famous mutants featured in the movie. So even if she will have nothing but a simple cameo, she still needs to be mentioned here.

This being said, when comparing the Jubilee from the comics with any of the other mutants featured in the movie, she is still the weakest of them all, even if her true powers have never been unleashed before.

Thus, besides being completely invisible to the Sentinels (which comes in handy, let's be honest) and besides being completely undetectable by powerful telepaths such as Psylocke, her main ability is pyrokinesis "“ she can shoot plasmoids from her hands, with various effects. Which is equal to nothing compared to what other mutants can do.

Of course, according to other characters, she may be more powerful than many, since these plasmoids are in fact small fusion reactions. But she doesn't unleash her true powers, since she is afraid of killing someone, so she is the last on this list.

As said, I don't know how X-Men: Apocalypse will use her. But I won't be surprised if she uses her cool-looking power just briefly in the movie.