The Cosmos Corps keeps track of thousands of worlds, but these thirteen are the ones that belong to the same local cluster as their headquarters, so they're the ones that get the most attention.
Adeia - The Corps' HQ is here, in the city of Sevenel. Eternally twilight, with a fixed constellation overhead. The area outside the city bears a strong resemblance to the Fringe and the Interstice.
Underville - A complicated and exponentially large network of tunnels, inhabited by the Underville Mice.
Lamppost Island - Home of the 13 Gryphons and the Crystal Shrine. Part of the same archipelago as Haffan Island.
Elseways - Modern-day city. Part of the same universe as Polywood, Port Sylvan, and Deco City.
The System - Home of the Bitkin.
The Holoverse - Adjacent to the System, but the two are distinct. A world of sentient computer programs and solid data.
Mondecart - Board/card game world.
Tessera - Should need no introduction. Home to Demons, Materians, and Synthians.
Fixed Earth - Earth, after a biological apocalypse resulting in most cities being overgrown and overtaken by artificial life forms called Fixls.
G - Junkyard's world. Little is known about it so far apart from a sharp social division between humans and Dogs.
Outer Edge - world of sentient spaceships; organic life is beneath their notice and so attempts to communicate with them have so far not gone well.
Immortal Imbalance - Urban Gothic sort of place.
Other Worlds
Macrocosm (destroyed)