I ran some quick numbers based on DTRPG. Some of my categorization may be iffy…

Mundane (8): WWWRPG, The Hood, Action Movie World, Deniable, Cartel, Spirit of 77, Bootleggers, Malandros

Fantasy (7): Dungeon World, Dungeon Planet, Freebooters on the Frontier, The Fellowship, Epyllion, City of Judas, Fallen Empires

Supers/Anime (6): Just Heroes, Worlds in Peril, Thrilling Powers, Magical Fury, Just A Game, Monster Force Terra

Urban Fantasy/Horror (5): Monster of the Week, Monsterhearts, Urban Shadows, tremulus, Mythos World

Cyberpunk (4): Headspace, The Sprawl, Cyberworld, The Veil

Post-apoc (2): Legacy, Apocalypse World

Wartime (2): Night Witches, MASHED

Space (2): Uncharted Worlds, CRUSH the REBELLION

Other (2): The Warren, Threadbare