Retrofitted Transmogrant

{3}{B}: Return Retrofitted Transmogrant from your graveyard to the battlefield tapped with two +1/+1 counters on it.

Death Baron

Skeletons you control and other Zombies you control get +1/+1 and have deathtouch.

Accursed Marauder

When Accursed Marauder enters, each player sacrifices a nontoken creature.

Diregraf Captain

Deathtouch
Other Zombie creatures you control get +1/+1.
Whenever another Zombie you control dies, target opponent loses 1 life.

Varina, Lich Queen

Whenever you attack with one or more Zombies, draw that many cards, then discard that many cards. You gain that much life.
{2}, Exile two cards from your graveyard: Create a tapped 2/2 black Zombie creature token.

Mindless Conscription

When Mindless Conscription enters and whenever you draw your third card each turn, amass Zombies 3. (Put three +1/+1 counters on an Army you control. It's also a Zombie. If you don't control an Army, create a 0/0 black Zombie Army creature token first.)

Diregraf Colossus

Diregraf Colossus enters with a +1/+1 counter on it for each Zombie card in your graveyard.
Whenever you cast a Zombie spell, create a tapped 2/2 black Zombie creature token.

Wayward Servant

Whenever another Zombie you control enters, each opponent loses 1 life and you gain 1 life.