A bunch of hacks with mostly graphical and musical changes, sometimes replacing cutscenes with videos and changing gameplay a little bit. Some of them fan made PC mods, stolen by pirates and remade for PS2.
GTA:SA Dragon Ball Z
Replaces main character with Vegeta and adds minor graphical changes.
Replaces main character with Wolverine and adds minor graphical changes.
Replaces main character with Saw.
GTA Dubai City
Major graphical hack, that remades San Andreas into Dubai. Replaces music.
GTA Kirk Douglas
Replaces main character with Kirk Douglas.
GTA Supernatural, GTA The Legend, GTA Infinite World, Gta 2012: End Of The World
These four is the same hack, with minor differences, that removes story missions and adds super powers.