GURPS 3x3 Eyes
A fan-worldbook for gaming in the 3x3 Eyes manga series by Yuzo Takada.
GURPS Discworld bye Nighte
A GURPS Discworld expansion for the darker side of Ankh-Morpork and Sundrye and Fyne Partes of the Dyske.
GURPS Dune
Sean Ware's detailed GURPS treatment of the Frank Herbert SF classic.
GURPS Godzilla
Jonathan Woodward's guide to GURPS roleplaying in the Toho universe. Includes filmography material, statistics for really big monsters, and crossover notes.
GURPS Marathon
A GURPS adaption of the popular science-fiction computer games from Bungie.
GURPS Shadow World Project
An adaptation of Iron Crown Enterprise's lost-but-not-forgotten fantasy world.
GURPS X-Files
A worldbook in Adobe Acrobat format by Gawain Jones, based on the fortean/mystery TV show.
In Nomine to GURPS Conversions
GURPS conversions originally written for the In Nomine core book, these predate the new GURPS In Nomine worldbook, and provide an alternate (now unofficial) approach to In Nomine in GURPS.
Net.GURPS.Characters.Book
A huge library of GURPS characters, ready-to-play.
Rico's GURPS Humanx Games
A large and growing collection of resources and expansion material for GURPS Humanx, including adventures, character adaptions from the novels, and starships.
Unofficial GURPS Star Wars Project
The ongoing project offers extensive free online supplements for download. Anyone interested in playing Star Wars with GURPS rules should have a look at those books.