Created to showcase the versatility of GURPS this is a pseudo time travel setting with two competing parachronic opposing organizations. The setting presupposes a bunch of alternate timelines and the characters travel from world to world doing various missions, This is a fun setting, though it can be hard on the GM as it jumps from world to world and mission assignments vary.
There are a number books and Pyramid articles supporting this setting.
This is the largest sci-fi setting for GURPS and started near the end of the Third Edition, but has had an update and conversion book as well as several fully Fourth Edition supplements.
The concept is a near future where transhumanism is front and center. Computer technology is prolific and humans can upload themselves into machines. Its similar to cyberpunk but less dystopic in a way.
Another Third Edition setting updated to Fourth Edition. This is a post Apocalypse series where computers took over the world. The difference between this and most others of that ilk is that there are several computers (called zone-minds) with each in charge of a certain region of the world (or beyond!) and they are vying with each other for control of resources and philosophies. This is a harsh world where computers send out hunter killer teams to eliminate a human resistance, use them as lab rats, or a labor force.
This is a Space Opera setting in the vein of pulp science fiction, with square jawed heroes, helpless damsels to rescue, and a lot of stereotypes. Its a fun setting and one not to be taken too seriously.
Another fun setting designed to be less than serious is Lands Out of Time which has a lost world with dinosaurs that the characters are somehow sent to.
So that 5 complete sci-fi settings for modern GURPS, two tongue in cheek, two serious and more gritty, and one that is pretty much anything goes. Pyramid has several setting ideas in it as well, and Third Edition settings can of course be adapted.
But that is what we have now, what would YOU like to see in the future?