[kupoartist]

From a list of "Independent Materia" (like Charlie's Angels?) There is
EXP Plus
Gil Plus
HP Plus
Luck Plus
Magic Plus
MP Plus
Speed Plus

There is no AP plus materia, the reason presumably being because AP growth for your materia is controlled by what weapons/armor you equip: The Fastest (Triple) growth slots are on Cloud's "Apocalypse" Sword and Cid's "Scimitar" lance, though you can only equip 3 or 2 Materia at a time (though do at least do a fair bit of damage though). You can get double-growth weapons and armlets for all characters.
You get the Apocalypse from the ancient forest and the Scimitar from the Submarine Docks at the Underwater Reactor

And it's very nice to see you back Macceh