Using mods to port new GTA Online content over to single player has developed something of its own sub-genre among GTA 5 mods. With Rockstar constantly updating Online with new content, missions and vehicles, but leaving the single player mode untouched since launch, it is up to players to keep expanding the solo experience. This is where mods come in to the picture, adding to or changing existing content in the story mode.

When modding started to catch on, many of the existing DLCs for GTA Online eventually made their way to single player. Vehicles, weapons and apartments which were previously Online exclusive were now accessible when playing alone. As new updates came out over time, the turnaround time between release and the completion of the porting mod decreased to just a day or two.
Currently, GTA 5 is more or less caught up with Online in terms of weapons and vehicles thanks to mods, however there is still a whole lot of content in Online which cannot be accessed with Franklin, Trevor or Michael.