Zombies love filling their graveyard with bodies to mass reanimate with Zombie Apocalypse and such, which a 2-drop like Butler helps set up
However, up until very recently, we've been pretty much in the dark about the set, save for a few pretty pieces of key art
In fact, the day that a mill deck becomes the topic of conversation for bannings probably means that we have already broken Commander beyond repair
But what exactly would a crystal counter be tracking
Ideal Zombie support cards will stock up the graveyard, reanimate Zombies for a fair price, give Zombies power/toughness boosts and use conventional removal and card draw effects to slowly but surely get ahead in casual games or Commander multiplayer games
Haste and trample are generally the most useful effects for Commander