My 100% Save Game for The Ballad of Gay Tony.
In this save game I have not used any cheats or mods!
I have done the following missions and activities in order to achieve 100%:
Completed All Storyline missions (Done with 100% scores).
Completed All 8 Nightclub missions.
Won a game of Air hockey, Golf, Pool and Darts.
Completed All Friend activities.
Completed All 5 Random Characters missions (Margo 2 missions, Arnaud 2 missions and Daisy 1 mission).
Danced successfully in Maisonette 9 and Hercules, also won the champagne drinking mini game.
Completed All 15 Base Jumps (wasn't going for 100% on those, but in the end most of them ended up at 100%, maybe 2-3 jumps are less than 100%).
Completed 50 Drug Wars (25 are required for 100% game completion, but I did 50 in order to unlock all the weapons in the safehouse).
Completed the 3 Triathlons.
Exterminated 50 seagulls.
Won the LC Cage Fight Championship.

I promised The Lost and Damned 100% Save Game, but Rockstar said no and the save got corrupted. After that I had no motivation to do it again so decided to go for The Ballad of Gay Tony instead. I will eventually do the Lost and Damned too.

Check out my profile for other GTA Save Games - https://www.gtainside.com/user/Ivelin