X
X-23
Xavier Institute for Higher Learning/Xavier's School for Gifted Youngsters
Xavier Institute Student Body
Xavier Shelter for Indigent Children
Xavier's Security Enforcers (XSE)
Xavier's Underground Enforcers (XUE)
X-Babies
X-Cell
X-Club
X-Corporation
X-Corps
X-Cutioner
X-Factor
X-Factor gen
X-Factor Investigations
(M Branch's) X-Force I
X-Force II
X-Man/Nate Grey
X-Men [X-mannen]
X-Men 2099
X-Nation 2099
Xorn I/Magneto III*
Xorn II
X-Peditioners 2099
X-Ranch
X-Statix/X-Force III
X-Terminators
X-Treme Sanctions Executive (XSE)
X-Treme X-Men

AppendiX: X
AppendiX: Teams X


* : overleden