Dont know if this is the best place to ask, but I was wondering if golarion had something similar to Sigil (from the d&d cosmology). I'm working on a bit of backstory for a character.
The closest thing I can think of would be the city/plane of Axis, where many lawful neutral aligned outsiders and deities make their home. Though it isn't the fulcrum point at the center of the multiverse like Sigil is.
While it's a terrestrial city on the material plane, if you're looking for inspiration or ideas for bringing Sigil into Golarion, I think that Kaer Maga has a very Planescape-esque feel with the plethora of weird creatures that live there and the various factions that run different sections of the city