In 1991, Marvel revised the entire lineup of X-Books, centered on the launch of a second X-Men series, simply titled X-Men. With the return of Xavier and the original X-Men to the team, the roster was split into two strike forces: Cyclops' "Blue Team" (chronicled in X-Men) and Storm's "Gold Team" (in Uncanny X-Men).
Its first issues were written by longstanding X-Men writer Chris Claremont and drawn and co-plotted by Jim Lee. Retailers pre-ordered this book at 8 million copies, but probably sold closer to 3 million copies.^[12] Another new X-book released at the time was X-Force, featuring the characters from The New Mutants, led by Cable; it was written by Rob Liefeld and Fabian Nicieza. Internal friction soon split the X-books' creative teams. In a controversial move, X-Men editor Bob Harras sided with Lee (and Uncanny X-Men artist Whilce Portacio) over Claremont in a dispute over plotting. Claremont left after only three issues of X-Men, ending his 16-year run as X-Men writer.^[13] Marvel replaced Claremont briefly with John Byrne, who scripted both books for a few issues. Byrne was then replaced by Nicieza and Scott Lobdell, who would take over the majority of writing duties for the X-Men until Lee's own departure months later when he and several other popular artists (including former X-title artists Liefeld, Portacio, and Marc Silvestri) would leave Marvel to form Image Comics. Jim Lee's X-Men designs would be the basis for much of the X-Men animated series and action figure line as well as several Capcom video games.
The 1990s saw an even greater number of X-books with numerous ongoing series and miniseries running concurrently. Notable story arcs of this time are "The X-Tinction Agenda" in 1990, "The Muir Island Saga" in 1991, "X-Cutioner's Song" in 1992, "Fatal Attractions" in 1993, "Phalanx Covenant" in 1994, "Legion Quest"/"Age of Apocalypse" in 1995, "Onslaught" in 1996, and "Operation: Zero Tolerance" in 1997. There were many new popular additions to the X-Men including Cable, Bishop, and Gambit — who became one of the most popular X-Men (rivaling even Wolverine in size of fanbase), but many of the later additions to the team came and went (Joseph, Maggott, Marrow, Cecilia Reyes, and a new Thunderbird). Xavier's New Mutants grew up and became X-Force, and the next generation of students began with Generation X, featuring Jubilee and other teenage mutants led and schooled by Banshee and former villainess Emma Frost at her Massachusetts Academy. In 1998, Excalibur and X-Factor ended and the latter was replaced with Mutant X, starring Havok stranded in a parallel universe. Marvel launched a number of solo series, including Deadpool, Cable, Bishop, Wolverine, X-Man, and Gambit, but few of the series would survive the decade.