The X-Men are finally slated to join the MCU, and all it cost us was the loss of yet another major film studio to the eldritch abomination known as Disney. ...Yay?
However, we are left with something of an issue. Fox has spent the past two decades putting out X-Men films in order to avoid giving Marvel their stuff back, so the American movie-going public are now very aware of many members of the Charles Xavier's uncanny group. So when Marvel reintroduces the X-Men, they have more fires to put out than just explaining how the hell mutants fit into the MCU to begin with (which to be fair, Marvel has been trying to do for years).
One way to circumvent the problem altogether is to introduce brand new mutant characters that the Fox movies never touched because their names weren't Wolverine.
For this list, we'll be ignoring the obvious picks like Cyclops, Xavier, Jean Grey and yeah, Wolverine, because of COURSE they're gonna be in the new movies. These are mutants that either have never appeared at all or didn't get the attention they deserved because, again, not Wolverine.