A fan on Reddit has designed a GTA 6 concept that combines all the major cities into one world.
GTA 6 leaked map concepts raise expectations for the real one
Should GTA 6 feature the biggest open-world map in history?
Every Grand Theft Auto 6/GTA Concept Map Ever - Mega Archive! : r/GTA6
GTA 6 Trailer Leak: Fans' Reaction To Characters, Gameplay and Graphics - Bloomberg
GTA 6 Revival blog Post – Do you remember GTA Vice: City? - Softonic
GTA 6 Map Concept (Made entirely with creative liberties and with nothing used from the leaks, also it's huge and isn't meant to be taken seriously) : r/GTA6
GTA 6 Leaks: Everything We Know about the Release Date, Gameplay, and More
GTA 6 Map - 2x Size Of Los Santos, 3 MAJOR Cities, 70% Enterable Buildings & MORE! (Trailer 1)
Every GTA Game Ranked - IGN
GTA VI MAP ANALYSIS - Predicting the GTA 6 Map from Trailer 1
GTA6 map concept blends all cities into a giant open world
GTA 6 Map LEAKED! It's HUGE! (Size, Number of Cities AND More!)
GTA 6 Physical Edition Should Continue This Tradition by Rockstar Games - EssentiallySports