Cerebro: Guide to the X-Men - Site includes indepth, historical character biographies, a message board, games, a picture gallery, fan-art, fan-fiction, and layouts of the X-mansion and grounds.
Children of the Atom - All mutants are featured here with an extensive character index including pictures, sounds and appearance lists. The site also offers writings on such topics as the Age of Apocalypse and other timelines, the Legacy Virus, and merchandising (including some tips on how to purchase safely online). Free downloads of wallpapers and Windows icons, fan-fiction and links are also included.
Chronology.net - An impressive attempt to show all the X-books in a chronological order with X-Men story timelines, title indices, and a bibliography.
The Danger Room - News, previews, a character database, images, and links.
The Freak Show - A mainly humoristic X-Men fansite with fanworks, downloads, contests, collections, links, and captivating trivia.
InvertedStripes - X-Men news, updates, images, video clips, audio, icons, statistics and downloads for fans of the comics, cartoons, and films.
Marvel Directory: The X-Men - This section of the full Marvel Directory site gives a history of the team and links to character bios for each member of the team, current, former and deceased. Information on Marvel villains is also included and there are also links to other X-Men and Marvel topics of interest.
Shocks Mutant World - X-Men community that offers a message board and detailed information on all the popular mutants.
Spacepirate's MUTANT X Page - Dedicated to the alternate universe of Mutant X, a now discontinued title. Offers an index featured characters, an issue guide and links.
Uncanny X-Men.Net - Character bios and indepth information on heroes and villains, picture galleries, fan contributions (art, fiction and film), free downloads, timeline histories and collector information.
UX-Gal ยท X-Men fansite - This site offers fan art, a large picture gallery, a message board, links, and activities for registered members.