Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Rise of the Dread Marn

Create X 2/2 black Zombie Berserker creature tokens, where X is the number of nontoken creatures that died this turn.
Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Graf Harvest

Zombies you control have menace. (They can't be blocked except by two or more creatures.)
{3}{B}, Exile a creature card from your graveyard: Create a 2/2 black Zombie creature token.

Liliana, Death's Majesty

+1: Create a 2/2 black Zombie creature token. Mill two cards.
−3: Return target creature card from your graveyard to the battlefield. That creature is a black Zombie in addition to its other colors and types.
−7: Destroy all non-Zombie creatures.

Sol Ring

Diregraf Captain

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

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

Go for the Throat

Appetite for Brains

Target opponent reveals their hand. You choose a card from it with mana value 4 or greater and exile that card.

Talisman of Dominance

{T}: Add {C}.
{T}: Add {U} or {B}. Talisman of Dominance deals 1 damage to you.

Shepherd of Rot

{T}: Each player loses 1 life for each Zombie on the battlefield.

Razorlash Transmogrant

Razorlash Transmogrant can't block.
{4}{B}{B}: Return Razorlash Transmogrant from your graveyard to the battlefield with a +1/+1 counter on it. This ability costs {4} less to activate if an opponent controls four or more nonbasic lands.

Undead Augur

Whenever Undead Augur or another Zombie you control dies, you draw a card and you lose 1 life.

Crawl from the Cellar

Return target creature card from your graveyard to your hand. Put a +1/+1 counter on up to one target Zombie you control.
Flashback {3}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Demolition Field

{T}: Add {C}.
{2}, {T}, Sacrifice Demolition Field: Destroy target nonbasic land an opponent controls. That land's controller may search their library for a basic land card, put it onto the battlefield, then shuffle. You may search your library for a basic land card, put it onto the battlefield, then shuffle.

Dark Ritual

Artificer's Hex

Enchant Equipment
At the beginning of your upkeep, if enchanted Equipment is attached to a creature, destroy that creature.

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Crowded Crypt

{T}: Add {B}.
Whenever a creature you control dies, put a corpse counter on Crowded Crypt.
{4}{B}{B}, {T}, Sacrifice Crowded Crypt: Create a 2/2 black Zombie creature token with decayed for each corpse counter on Crowded Crypt. (A creature with decayed can't block. When it attacks, sacrifice it at end of combat.)

Dimir Signet

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

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.)

Cleaver Skaab

{3}, {T}, Sacrifice another Zombie: Create two tokens that are copies of the sacrificed creature.

Submerged Boneyard

Submerged Boneyard enters tapped.
{T}: Add {U} or {B}.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Headless Rider

Whenever Headless Rider or another nontoken Zombie you control dies, create a 2/2 black Zombie creature token.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters, each opponent loses X life, where X is your devotion to black. You gain life equal to the life lost this way. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Paradox Haze

Enchant player
At the beginning of enchanted player's first upkeep each turn, that player gets an additional upkeep step after this step.

Ice Tunnel

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

Zombie Apocalypse

Return all Zombie creature cards from your graveyard to the battlefield tapped, then destroy all Humans.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Trepanation Blade

Whenever equipped creature attacks, defending player reveals cards from the top of their library until they reveal a land card. The creature gets +1/+0 until end of turn for each card revealed this way. That player puts the revealed cards into their graveyard.
Equip {2}

Fell Stinger

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

Fleshbag Marauder

When Fleshbag Marauder enters, each player sacrifices a creature of their choice.

Overcharged Amalgam

Flash
Flying
Exploit (When this creature enters, you may sacrifice a creature.)
When Overcharged Amalgam exploits a creature, counter target spell, activated ability, or triggered ability.

Gisa and Geralf

When Gisa and Geralf enters, mill four cards.
Once during each of your turns, you may cast a Zombie creature spell from your graveyard.

Skull Skaab

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

Secluded Courtyard

As Secluded Courtyard enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

Shambling Ghast

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

Johnny, Combo Player

{4}: Search your library for a card, put that card into your hand, then shuffle.

Counterspell

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.

Swamp

Falcon Abomination

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

Jwar Isle Refuge

Jwar Isle Refuge enters tapped.
When Jwar Isle Refuge enters, you gain 1 life.
{T}: Add {U} or {B}.

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.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Geralf, Visionary Stitcher

Zombies you control have flying.
{U}, {T}, Sacrifice another nontoken creature: Create an X/X blue Zombie creature token, where X is the sacrificed creature's toughness.

Gleaming Overseer

When Gleaming Overseer enters, amass Zombies 1. (Put a +1/+1 counter 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.)
Zombie tokens you control have hexproof and menace.

Champion of the Perished

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

Black Market

Whenever a creature dies, put a charge counter on Black Market.
At the beginning of your first main phase, add {B} for each charge counter on Black Market.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Darkslick Shores

Darkslick Shores enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {B}.

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

Island

Jadar, Ghoulcaller of Nephalia

At the beginning of your end step, if you control no creatures with decayed, create a 2/2 black Zombie creature token with decayed. (It can't block. When it attacks, sacrifice it at end of combat.)

Death Baron

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

Crux of Fate

Choose one —
• Destroy all Dragon creatures.
• Destroy all non-Dragon creatures.

Withengar Unbound

Flying, intimidate, trample (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a player loses the game, put thirteen +1/+1 counters on Withengar Unbound.

Elbrus, the Binding Blade

Equipped creature gets +1/+0.
When equipped creature deals combat damage to a player, unattach Elbrus, the Binding Blade, then transform it.
Equip {1}

Elbrus, the Binding Blade // Withengar Unbound

Josu Vess, Lich Knight

Kicker {5}{B} (You may pay an additional {5}{B} as you cast this spell.)
Menace
When Josu Vess, Lich Knight enters, if it was kicked, create eight 2/2 black Zombie Knight creature tokens with menace.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Crush of Tentacles

Surge {3}{U}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Return all nonland permanents to their owners' hands. If this spell's surge cost was paid, create an 8/8 blue Octopus creature token.

Open the Graves

Whenever a nontoken creature you control dies, create a 2/2 black Zombie creature token.

Dismal Backwater

Dismal Backwater enters tapped.
When Dismal Backwater enters, you gain 1 life.
{T}: Add {U} or {B}.

Shambling Goblin

When Shambling Goblin dies, target creature an opponent controls gets -1/-1 until end of turn.

Cemetery Reaper

Other Zombie creatures you control get +1/+1.
{2}{B}, {T}: Exile target creature card from a graveyard. Create a 2/2 black Zombie creature token.

Rooftop Storm

You may pay {0} rather than pay the mana cost for Zombie creature spells you cast.

Dimir Locket

{T}: Add {U} or {B}.
{U/B}{U/B}{U/B}{U/B}, {T}, Sacrifice Dimir Locket: Draw two cards.

Drown in the Loch

Choose one —
• Counter target spell with mana value less than or equal to the number of cards in its controller's graveyard.
• Destroy target creature with mana value less than or equal to the number of cards in its controller's graveyard.

Vile Entomber

Deathtouch
When Vile Entomber enters, search your library for a card, put that card into your graveyard, then shuffle.

Lord of the Accursed

Other Zombies you control get +1/+1.
{1}{B}, {T}: All Zombies gain menace until end of turn.

Endless Ranks of the Dead

At the beginning of your upkeep, create X 2/2 black Zombie creature tokens, where X is half the number of Zombies you control, rounded down.

Carrion Feeder

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

Zombie Master

Other Zombie creatures have swampwalk. (They can't be blocked as long as defending player controls a Swamp.)
Other Zombies have "{B}: Regenerate this permanent."

Necroduality

Whenever a nontoken Zombie you control enters, create a token that's a copy of that creature.

Army of the Damned

Create thirteen tapped 2/2 black Zombie creature tokens.
Flashback {7}{B}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Victimize

Choose two target creature cards in your graveyard. Sacrifice a creature. If you do, return the chosen cards to the battlefield tapped.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Gravecrawler

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

Kindred Discovery

As Kindred Discovery enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Liliana's Mastery

Zombies you control get +1/+1.
When Liliana's Mastery enters, create two 2/2 black Zombie creature tokens.

Bloodletter Quill

{2}, {T}, Put a blood counter on Bloodletter Quill: Draw a card, then you lose 1 life for each blood counter on Bloodletter Quill.
{U}{B}: Remove a blood counter from Bloodletter Quill.

Command Tower

Ghoulraiser

When Ghoulraiser enters, return a Zombie card at random from your graveyard to your hand.

Syphon Flesh

Each other player sacrifices a creature. You create a 2/2 black Zombie creature token for each creature sacrificed this way.

Mystic Remora

Cumulative upkeep {1} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
Whenever an opponent casts a noncreature spell, you may draw a card unless that player pays {4}.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

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.

Dreadmalkin

Menace (This creature can't be blocked except by two or more creatures.)
{2}{B}, Sacrifice another creature or planeswalker: Put two +1/+1 counters on Dreadmalkin.