VI: Gogo, Mog, Umaro, Strago, Relm, Setzer, Gau, and Cyan. I only really used Sabin, Terra, Celes, and Locke, and sometimes Edgar and Shadow. The rest sucked, in my opinion.
X: Kimahri, just because...well, he's Kimahri. And he couldn't do much damage unless he was in Overdrive.