The classes that you can use are (excluding "special" classes such as Engineer or Holy Knight [one of my favorites]) Squire, Chemist, Knight, Archer, Priest, Wizard, Summoner, Ninja, Geomancer, Mediator, Mime, Calculator, Dancer, Samurai, Bard, Time Mage and Monk. If I didn't get them all, feel free to add! Remember, I only listed the MAIN classes, not the special ones.