Airship: (FFI) (FFIII) (FFIV) (FFVII) (FFVIII) (FFIX) (FFX) (FFXI) (FFXII)
Alexander: (FFVII) (FFVIII) (FFIX)
ATB: (FFVII) (FFIX)
Bahamut: (FFI) (FFIII) (FFVIII) (FFIX) (FFX) (FFXI)
Black Mage: (FFI) (FFIII) (FFIX)
Blind: (FFVII) (FFIX)
Boats/ships: (FFII) (FFIX)
Card Games: (FFVIII) (FFX)
Changeable Character Names: (FFI) (FFIX)
Character Voices/Speaking: (FFX) (FFX-2) (FFXII)
Chocobos: (FFIII) (FFVI) (FFVII) (FFIX) (FFX) (FFXI) (FFXII)
Cid: (FFT)(FFII) (FFIII) (FFVIII) (FFIX) (FFX) (FFXI)
Cloud Strife: (FFVII) (FFVIIDOC) (FFVIICC) (FFVIIAC) (FFT) (KH) (KHII) (FFVIILO) ((KHIICOM))
Garland: (FFI) (FFIX)
Guaranteed 9999 hit all attacks: (FFVII) (FFIX)
Holy: (FFI) (FFIX)
Ifrit: (FFVII) (FFIX) (FFXI)
Ixion: (FFX) (FFXI)
Job System: (FFIII) (FFV) (FFX-2) (FFT) (FFXI)
Moogles: (FFVI) (FFIX) (FFXI) (FFXII) (FFT) (FFTA) (KH) (KHII)
Moving on world maps: (FFI) (FFII) (FFIII)
Ninja class: (FFVII) (FFIX) (FFXI)
Odin: (FFVII) (FFVIII) (FFIX)
Potions: (FFVII) (FFVIII) (FFIX) (FFX) (FFX-2) (FFXI) (FFT)
Ramuh: (FFVI) (FFIX) (FFXI)
Regen: (FFVII) (FFVIII) (FFIX)
Ribbon: (FFVII) (FFIX) (FFXI)
Shiva: (FFVII) (FFVIII) (FFIX) (FFX) (FFXI) (FFXIII)
Silence: (FFVII) (FFVIII) (FFIX) (FFXII)
Songstress/Dancer class: (FFT) (FFX-2) (FFXI)
Tents: (FFVIII) (FFIX) (FFI)
Thief class: (FFT) (FFIII) (FFIX) (FFXI)
(go right ahead, also since the list is getting so friggin big, does anyone want to start writing what they added?)