I have a selection of custom datafiles for GCA at the
MyGURPS GCA Page with the following:
1. A GDF that adds in my house rules, for those who like them. It causes Per and Will to be based off of 10 (instead of IQ), reduces the value of age-related traits, fixes Arm ST/DX, adds the Diabetic disadvantage, includes several new Modifiers for advantages, and more. Check out the main
MyGURPS page (link in my .sig) for details.
2. A GDF that adds the rules for Ritual Magic with two tweaks to improve it and prevent abuse: Path skills no longer default to core skills and spells are Average techniques instead of Hard. Small changes, but they really improve the Ritual Magic rules, in my experience.
3. The GDF for GURPS Mysteries, which is now part of the official data update. If and when I get around to converting the Professional Templates, you'll see them here first.
4. A GDF compilation of Talents and Wildcard! Skills -- all of the official ones from the various sourcebooks (so you don't have to include every single GDF in your dataset just to get the Talents) plus the best of the best from right here in the forums. I really recommend this one for the homebrew stuff alone.
5. (Just added) The GDF-in-progress for our GURPS Star Trek game. Not very polished, but it's got Starfleet Enlisted, Starfleet Academy, and Klingon Marine templates; rules, skills, and equipment for the Bat'leth; and racial templates for Klingons, Ullians (they were in one TNG episode) and an amphibious player-created race, the Nadissians.
Instructions: I've also included a set of instructions explaining how to download, save, and install these files for anyone not familiar with the process.
Feel free to
look through and download any of these files and use them if you like them.