Netland: GURPS died, so here's its revival!
Netland is a setting of my own creation, in which the Earth has been destroyed by a forgotten cataclysm and everyone now lives in a massive-scale computer simulation.
The simulation includes vast expanses of space, as well as every fictional setting and character the maintaining AI could find.
No-one remembers the Earth; the simulation is a couple thousand generations old. There are seven God-AIs that maintain the universe from outside, but they rarely come into play in the game so I won't list them this time.