The fifth toughness in a format with multiple pieces of four-toughness removal is a good start for example
Legendary Creature - Nightmare Drivnod, Carnage Dominus If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time
Vigor reskinned as Heralds of the Shredder TAP INTO TURTLE POWERMagic gets a quadruple dose of mutagenic mayhem as the Teenage Mutant Ninja Turtles make their debut on the battlefield
One Dragonlord Atarka makes Earthquake Dragon a reasonably castable card before considering creatures like Dragonlord's Servant and Dragonspeaker Shaman that reduce the casting cost further
And it hits like a truck combined with ways to protect it from removal like Thalia, Guardian of Thraben and Reidane, God of the Worthy
This represents the extreme end of Pokmon card scarcity: when fewer than 2 dozen copies survive and only 1 is in perfect condition, prices enter territory usually reserved for fine art