(When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.) This creature has persist as long as you control a black creature
This can take someone out of the game with just one attack, as you only need it to have ten power to one-shot someone
Anything that adds +1/+1 counters en masse could be useful as well
Absolute Virtue Aettir and Priwen Ancient Adamantoise Buster Sword Clive, Ifrit's Dominant Cloud, Midgar Mercenary Cloud, Planet's Champion Dark Confidant Emet-Selch, Unsundered Esper Terra Gogo, Master of Mimicry Hades, Sorcerer of Eld Ifrit, Warden of Inferno Kefka, Court Mage Kefka, Ruler of Ruin Lightning, Army of One Nibelheim Aflame Sephiroth, Fabled SOLDIER Sephiroth, One-Winged Angel Sephiroth, Planet's Heir Summon: Bahamut Summon: Knights of Round Terra, Magical Adept Traveling Chocobo Vivi Ornitier Y'shtola Rhul Yuna, Hope of Spira
Test of endurance was a favorite card from Judgement when it was released
Otherwise, you just find all that are there
