Itemizing the various games sounds fun, so here I go:
1: Matoya, I guess? I liked the music in her cave, and the brooms. Not much character development in the first one, so that's all I got.
2 & 3: I didn't play them much, so I have no idea. Again, didn't seem like there was much development.
4: Rubicant. He was classy and honorable. Stupid Edge and his stupid "powers of rage" or whatever..
5: Galuf. Cool name, and he kicks ass for an old guy. He sneaks around Exdeath's palace and saves everyone else in his own little solo section.
6: Setzer. Not entirely sure why. I guess I like his aesthetic, and that he seems to respect the party for playing him. His backstory is decent.
7: I guess I'll have to go with Tifa? I didn't like ff7 much, but if I remember correctly, Tifa hangs around and gets the job done and does her thing in the background, and eventually gets her guy, without any kinda magical flower-girl lifestream crap. She's a trooper.
Tactics: Delita, Zalbag, Dycedarg, MC, Ovelia, Wiegraf, Algus.. Tactics has such better characters than the main franchise.. but overall Delita. He's so damn sympathetic and such a freakin' asshole at the same time. Powerhouse of a character. I don't want to spoil anything.
8: hated this one.. uh.. I guess the guy who turned out to be the MC's dad was kinda OK.
9: didn't play it. So, uh.. not the one with the tail.
10 / X: all the characters in this one pissed me off except Auron and Kimhari, so uh.. Auron.
X-2: No.
11: never played it.
12: I forget his name, but.. the big bad guy's younger brother. He was hella savvy for a kid. I never beat FF12 (and I skipped a lot of the later cutscenes, so I dunno..), but I was rooting for him to someday take over the empire. Balthier was pretty good, too, and Basch and Ashe were decent. Vaan/Penelo/Fran sucked ass by comparison, and never made it into my active party once I got the full coterie.
So, overall, Delita by a landslide.