Sadly, I think IX is the only one I've beaten more than once. I've beaten I once, am working on II, am really bored of III, beat IV once, beat V once, beat VI, Beat VII, can't be bothered with VIII, beat X once can't afford XI and am working on XII. Oh wait, I beat Crisis Core twice and TA2 twice, but idk if they count cuz they aren't main series.

If it counts, I've beaten all three of the KH games like five times each by now haha.