This is definitely going to take a decade.

Unless if you can shorten the list into playable characters and villain or you allow us to hit and heal for 100

Since I love summons:

Heal Ixionx2

CREATURE CLASS
Alexander 300
Anima 300
Ark 300
Atomos 300
Bahamut 360
Bahamut Neo 300
Bahamut Zero 300
Behemoth 300
Bismark 300
Brothers 300
Cactaur 300
Carbunkl/Carbuncle 300
Cerberus 300
Choco/Mog 300
Chubby Chocobo 300
Cindy 300
Crusader 300
Cyclops 300
Diablos 300
Doomtrain 300
Eden 300
Fairy 300
Fenrir 300
Gilgamesh 300
Golem 300
Griever 300
Hades 300
Ifrit 300
Ixion 360
Kappa 300
Kirin 300
Kjata 300
Knights of the Round 300
Leviathan 300
Lich 300
Maduin 300
Madeen 300
Mindy 300
Moogle/Mini Mog 300
Moomba 300
Odin 300
Palidor 300
Pandemona 300
Phantom 300
Pheonix 300
Quezticotl 300
Ragnarok 300
Raiden 300
Ramuh 300
Unicorn 300
Salamander 300
Sandy 300
Shiva 300
Shoat 300
Silf 300
Siren 300
Sraphim 300
Starlet 300
Stray 300
Tiamat 300
Terrato 300
Titan 300
Tonberry 300
Typhoon 300
Valefor 300
Yojimbo 300
Zodiac 300
ZoneSeek 300