Its obnoxiously powerful, its flexible and its a board wipe that doesnt hit your stuff at all, while obliterating everyone elses
Esper Sentinel's power grows as its stats grow, something that Human decks can accomplish quite easily
Elenda, the Dusk Rose [Best Vampire Commander for Sacrifice Decks] Elenda gets bigger every time something dies, and when she finally exits the battlefield, she floods the board with Lifelink Vampires equal to her power easily one of the best Vampire Commanders MTG has for aristocrats that just wont quit
Oh, and it transforms into the game-ending Aang and La, Ocean's Fury
Meanwhile, decks like Familiars and Goblins (Moggwarts) boast very high conversion rates, reflecting how often they appear in top results relative to how often they are played
Skyclave Relic is a decent enough mana rock