Which forms are a character's "signature" form?

[Papasmurf]

With Goku I'd say regular SSJ is his signature due to him using it the most, plus he stopped using SSJ3 in Super for the most part and Blue is just a recolor of it. He still hasn't used UI long enough for it to be his signature form. In GT SSJ4 is definitely his signature form though.

Gohan's signature would just be Ultimate at this point since it was his ceiling until he acquired Gohan Beast. If it were CG Gohan it'd be SSJ2 for sure though.

It's harder to say with Vegeta since he has used SSJ2 in even less battles than Goku has overall and he doesn't really emply his God forms more than Goku. I'd probably go with regular Blue and Evolved for Vegeta since the form he whipped out before anyone else (Grade 2) got scrapped at the speed of light.

Future Trunks can be associated well with both SSJg3 and SSJ2. SSJ Rage would be up there if he used it at all in Heroes.

The Goku/Vegeta fusions can be associated well with regular SSJ and Blue since those are the only forms they employed outside of GT.

Gotenks' signature form would definitely be SSJ3 as he's almost always playable in that form in video games and it's his highest transformation.

Freeza's signature form would be 4th form and the fact that his transformations above it are recolors speaks to how much more iconic it is than his previous 3 forms.

Cell's signature form would be his Perfect form.

Boo is well associated with both his Fat and Kid forms.

 

[Hector]

-Goku: SSJ, since sooner or later, he always replaces any other form with it.
-Vegeta: SSJ, since he's Goku's alter ego.
-Trunks: Grade 3 is too awkward for a signature form. Maybe Grade 2.
-Kid Gohan: SSJ2.
-Adult Gohan: Ultimate.
-Gotenks: SSJ3 was too short-lived, and Gotenks is a gag character who has never won a fight in his life anyway, so we might as well leave him in his base form.
-Vegetto/Gogeta: SSJ Blue, or SSJ if you don't like DBS.
-Freeza: 4th form in the 50% suppression, since that's his version that shone the most.
-Cell: Perfect Form in the suppression he fought Goku in. His full-power form, in which he buffed his muscles a little in the anime filler, never got a chance to be really tested, since he went full power only to have his ass delivered by Gohan.
-Buu: Kid, because that was the real Buu.

 

[GreatSaiyaman123]

I think Trunks is between SSJ1 and SSJ Rage, depending on the series. He was already pretty jacked without the Grade forms in Z.