List of X Men members

New Mutants graduate X-Men (1986)

While the X-Men were de-aged, the New Mutants briefly graduated to become X-Men in Uncanny X-Men Annual #10 (1986).

Muir Island X-Men (1989)

In the wake of the X-Men's "death" during "Fall of the Mutants," a team of X-Men assembled on Muir Island in Uncanny X-Men #254-255 (1989).

Phalanx invasion X-Men (1994)

To oppose the threat of the techno-organic alien Phalanx, a team of X-Men was quickly banded together in Uncanny X-Men #316 (1994).

Mannite rescue X-Men (1999)

After Professor X disbanded the X-Men in an attempt to "smoke out" a Skrull impostor in their ranks, Cyclops and Jean Grey pulled together a team to help the Mannites in Astonishing X-Men, vol. 2 #1 (1999).

Genoshan assault X-Men (2001)

After losing members when Storm started her X-Treme X-Men and Professor X was captured by Magneto, Jean Grey recruits a temporary team in Uncanny X-Men #392 (2001) in order to rescue Professor X.

Street team X-Men (2004)

A team scratched together by Cyclops in the wake of Xorn's rampage through Manhattan in New X-Men, vol. 1 #149–150 (2004).

X-Force (X-Men's strike team) (2007–2014)

X-Men squad assembled and led by Cyclops with Wolverine serving as the field leader. Took on missions which required responses too violent or controversial for the X-Men to deal with directly. When Cyclops disbanded X-Force, Wolverine put a new X-Force squad together without his knowledge.

X-Club / science team (2009–2012)

Beast gathered a scientific squad to attempt to deal with the mutant birth crisis and reverse the effects of M-Day (Uncanny X-Men #507 [2009]).

The Lights (2010–2012)

A team of the first mutants to surface in Earth since M-Day, tasked with rescuing and helping any other new mutants as they appear.

X-Force (Cable founded) (1991–2001, 2012–2015)

The members of the New Mutants decided to change the team name to X-Force in New Mutants #100 (1991).

Xavier Institute Students

It was stated that there were 182 Xavier Institute students enrolled before M-Day (2006), after which they were reduced to 26, including X-23 (plus Kid Omega in Beast's lab). Those who did not show up in New X-Men, vol. 2 #23 (2006) are most likely depowered or even dead (42 died on the bus explosion in New X-Men, vol. 2 #23 [2006]).

New X-Men (2006–2008)

The team debuted in New X-Men, vol. 2 #23 (2006) after a last-man-standing exercise to know which students were the most worthy to be trained. Wallflower, Blindfold, Ernst, and Gentle had been excused from the exercise. The students selected were to be trained as a junior team of X-Men. Disbanded as of X-Men, vol. 2 #207 (2008).

Young X-Men (2008–2009)

A group of former Xavier Institute students originally brought together by Donald Pierce, disguised as Cyclops and later mentored by Dani Moonstar and Sunspot as a new, young X-Men squad.

Students with no squad known (2003–2006)

Here are the students who were shown but whose squads are not known or who died or left the Institute before joining one. It is likely that some of them were members of squads whose full rosters have not yet been revealed, including the Exemplars, the Excelsiors, the Paladins, Storm's squad, and possibly the Chevaliers.

Unofficial

The following are teams who have used the name of X-Men without express permission of the official X-Men, sometimes opposed to the X-Men altogether, to announce and/or promote themselves to the public.

Great Lakes X-Men (2005–2006)

Served a cease and desist for his team's use of the Avengers name, Mr. Immortal reorganized the Great Lakes Avengers into a team of unofficial X-Men. They have since changed their name to first Great Lakes Champions and then Great Lakes Initiative.

Norman Osborn's X-Men (2009–2010)

A team of X-Men assembled by Norman Osborn during the "Utopia" storyline as part of the overarching "Dark Reign" event.