Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Wilhelt, the Rotcleaver

Whenever another Zombie you control dies, if it didn't have decayed, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)
At the beginning of your end step, you may sacrifice a Zombie. If you do, draw a card.

Sol Ring

Gravecrawler

Gravecrawler can't block.
You may cast Gravecrawler from your graveyard as long as you control a Zombie.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Carrion Feeder

Carrion Feeder can't block.
Sacrifice a creature: Put a +1/+1 counter on Carrion Feeder.