Rockstar is putting its foot down: no more graphic mods in GTA Online.
GTA BOOM has covered the most popular and most advanced graphical mods out there quite extensively — however, will they get you banned from GTA Online?

These mods allow PC users to drastically enhance the visuals of GTA V by adding extremely high resolution textures to the game, as well as new visual effects and tweaks to existing ones. The kinds of results these mods have achieved are nothing less than astounding, with the most popular ones creating a near photo-realistic graphics while playing — provided you have a rig powerful enough to run it.
Now, these graphical mods increase visual fidelity and improve special effects, but they don't affect gameplay — or do they? The question whether or now strictly visual mods are allowed in GTA Online has been one even Rockstar Support hasn't been able to answer for a good long while. Players have spoken of instances when even after a 6 response ticket was closed, the support representative still could not provide a clear answer as to whether or not its use is a bannable offense.
Some users of SweetFX have, surprisingly, gotten positive response from Rockstar.