now if you'll excuse me I need to start deep diving on G3 team compositions
Does it do damage? It works on a G3 team.
But seriously, any rainbow heavy hitters with good utility specials. Healers in particular are useful for G3 since he can't use meat without a big sacrifice in damage. Damage reducers if you want. Delayers as always are good, especially since one of the weaknesses of G3 is a big group of mobs with 1 turn cooldown.
One thing to note is that all your damage is coming from your last three characters, so it often helps to prioritize utility specials over damage for a few units. But having a whole team of different type heavy hitters of course means you can get that huge multiplier on any type you need.
My current go to G3 team is: G3/G3/Boa/Sabo/Doflamingo/GPU
The only issue is that Doflamingo doesn't get the Sabo special damage boost, but Sabo, Boa, and G3 do. And since Sabo is a two turn burst, I could toss a free spirit orb locker in there (don't have Aoikiji yet, but he's a good fit). Or a conditional booster like Monet. There are a lot of options depending on how much of a burst is desired.