Yes, there have been a handful of major GTA 6 leaks, including actual visuals from the game. Footage of the upcoming GTA was released, and even though Rockstar tried to erase it from the internet as fast as possible, it was too late.
Around 90 short videos of gameplay were leaked by a hacker and confirmed by Rockstar. It should be mentioned, however, that all of the footage was early gameplay footage and do not necessarily reflect what the game will look like at the final stages.
One of the more interesting details shown by the leaked footage is that the franchise will, in fact, be returning to Vice City, Florida – one of the previous locations adored by fans.
For what it’s worth, I would recommend following reputable blogs such as Gamer Essential so that you’re notified whenever a major leak occurs, including GTA 6 leaks.