D&D --> Ptolus, Freeport (this has a version without system), etc.
Shadow world RM --> Eidolon and Sel-kai city or the new version Eidolon city by the sky, Haalkitaine and the Imperial Court.
Warhammer --> Marienburg and Middenheim. The 2nd edition has some books with some pages for a city and adventure like Terror in Talabheim.
Fantasy Hero --> Valdorian age setting is a bit like Conan, it has 60 pages for a city.
MERP --> Minas Tirith
Pathfinder --> Guide to Korvosa + Curse of the crimson throne campaign.