The only single player ones I’ve ever played have been 1 and 7. 1 was…old. The mechanics and everything remind me of Dragon Warrior but I kind of honestly just prefer Dragon Warrior (although I guess that one is also nostalgic because I remember watching my dad play it as a kid).
7 is much more modern but still pretty old at this point. It has a good story and interesting characters. It’s been a while and I don’t remember what the actual gameplay was like but I don’t remember it being turn based.
I’ve also watched my BF play quite a bit of Final Fantasy Tactics and that’s just what it sounds like, a very tactical turn based game. Not for me but some people really like that style of game so that’s something to look into if it appeals to what you’re looking for.
I also played a little bit of Final Fantasy 14 online and it was fun, although not the styles of MMO I personally prefer. But again it’s all personal preference and if you like MMOs you should look it up because you might want to consider that instead of one of the single player games.