Necroduality

Whenever a nontoken Zombie enters the battlefield under your control, create a token that's a copy of that creature.

Archghoul of Thraben

Whenever Archghoul of Thraben or another Zombie you control dies, look at the top card of your library. If it's a Zombie card, you may reveal it and put it into your hand. If you don't put the card into your hand, you may put it into your graveyard.

Narfi, Betrayer King

Other snow and Zombie creatures you control get +1/+1.
{S}{S}{S}: Return Narfi, Betrayer King from your graveyard to the battlefield tapped. ({S} can be paid with one mana from a snow source.)

Shambling Ghast

When Shambling Ghast dies, choose one —
• Brave the Stench — Target creature an opponent controls gets -1/-1 until end of turn.
• Search the Body — Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Champion of the Perished

Whenever another Zombie enters the battlefield under your control, put a +1/+1 counter on Champion of the Perished.

Flip the Switch

Counter target spell unless its controller pays {4}. Create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Organ Hoarder

When Organ Hoarder enters the battlefield, look at the top three cards of your library, then put one of them into your hand and the rest into your graveyard.

Priest of the Haunted Edge

{T}, Sacrifice Priest of the Haunted Edge: Target creature gets -X/-X until end of turn, where X is the number of snow lands you control. Activate only as a sorcery.

Fell Stinger

Deathtouch
Exploit (When this creature enters the battlefield, you may sacrifice a creature.)
When Fell Stinger exploits a creature, target player draws two cards and loses 2 life.

Snow-Covered Swamp

Falcon Abomination

Flying
When Falcon Abomination enters the battlefield, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Bladestitched Skaab

Snow-Covered Island

Ice Tunnel

({T}: Add {U} or {B}.)
Ice Tunnel enters the battlefield tapped.

Skull Skaab

Exploit (When this creature enters the battlefield, you may sacrifice a creature.)
Whenever a creature you control exploits a nontoken creature, create a 2/2 black Zombie creature token.

Stitched Assistant

Exploit (When this creature enters the battlefield, you may sacrifice a creature.)
When Stitched Assistant exploits a creature, scry 1, then draw a card. (To scry 1, look at the top card of your library, then you may put that card on the bottom of your library.)