Unseal the Necropolis

Each player mills three cards. Then you return up to two creature cards from your graveyard to your hand. (To mill three cards, a player puts the top three cards of their library into their graveyard.)

Gloomfang Mauler

Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)
Backup 2 (When this creature enters, put two +1/+1 counters on target creature. If that's another creature, it gains the following ability until end of turn.)
Menace

Scaretiller

Whenever Scaretiller becomes tapped, choose one —
• You may put a land card from your hand onto the battlefield tapped.
• Return target land card from your graveyard to the battlefield tapped.

Charcoal Diamond

Charcoal Diamond enters tapped.
{T}: Add {B}.

Entropic Decay

Mill four cards. (Then exile this card. You may cast the creature later from exile.)

Gray Slaad

As long as there are four or more creature cards in your graveyard, Gray Slaad has menace and deathtouch.

Gray Slaad // Entropic Decay

Bojuka Bog

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

Necromancer's Assistant

When Necromancer's Assistant enters, mill three cards.

Injector Crocodile

When Injector Crocodile dies, incubate 3. (Create an Incubator token with three +1/+1 counters on it and "{2}: Transform this artifact." It transforms into a 0/0 Phyrexian artifact creature.)
Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Songs of the Damned

Add {B} for each creature card in your graveyard.

Defile

Target creature gets -1/-1 until end of turn for each Swamp you control.

Deadly Visit

Destroy target creature.
Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Tithebearer Giant

When Tithebearer Giant enters, you draw a card and you lose 1 life.

Shamble Back

Exile target creature card from a graveyard. Create a 2/2 black Zombie creature token. You gain 2 life.

Coastal Bulwark

Defender
Coastal Bulwark gets +2/+0 as long as you control an Island.
{2}, {T}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Coffin Purge

Exile target card from a graveyard.
Flashback {B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Hand of Emrakul

You may sacrifice four Eldrazi Spawn rather than pay this spell's mana cost.
Annihilator 1 (Whenever this creature attacks, defending player sacrifices a permanent of their choice.)

Recover

Return target creature card from your graveyard to your hand.
Draw a card.

Corrupt

Corrupt deals damage to any target equal to the number of Swamps you control. You gain life equal to the damage dealt this way.

Corpse Churn

Mill three cards, then you may return a creature card from your graveyard to your hand. (To mill three cards, put the top three cards of your library into your graveyard.)

Funeral Rites

You draw two cards, lose 2 life, then mill two cards.

Cadaver Imp

Flying
When Cadaver Imp enters, you may return target creature card from your graveyard to your hand.

Twisted Abomination

{B}: Regenerate Twisted Abomination. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)
Swampcycling {2} ({2}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Eldrazi Devastator

Maelstrom Colossus

Cascade (When you cast this spell, exile cards from the top of your library until you exile a nonland card that costs less. You may cast it without paying its mana cost. Put the exiled cards on the bottom in a random order.)

Nighteyes the Desecrator

{4}{B}: Put target creature card from a graveyard onto the battlefield under your control.

Nezumi Graverobber

{1}{B}: Exile target card from an opponent's graveyard. If no cards are in that graveyard, flip Nezumi Graverobber.

Nezumi Graverobber // Nighteyes the Desecrator

Grave Scrabbler

Madness {1}{B} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
When Grave Scrabbler enters, if its madness cost was paid, you may return target creature card from a graveyard to its owner's hand.

Tortured Existence

{B}, Discard a creature card: Return target creature card from your graveyard to your hand.

Cremate

Exile target card from a graveyard.
Draw a card.

Barrier of Bones

Defender
When Barrier of Bones enters, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Mire Triton

Deathtouch
When Mire Triton enters, mill two cards and you gain 2 life. (To mill a card, put the top card of your library into your graveyard.)

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

Crow of Dark Tidings

Flying
When this creature enters or dies, mill two cards. (Put the top two cards of your library into your graveyard.)

Atrocious Experiment

Target player mills two cards, draws two cards, and loses 2 life. (To mill a card, a player puts the top card of their library into their graveyard.)

First-Sphere Gargantua

When First-Sphere Gargantua enters, you draw a card and you lose 1 life.
Unearth {2}{B} ({2}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Myr Retriever

When Myr Retriever dies, return another target artifact card from your graveyard to your hand.

Tormod's Crypt

{T}, Sacrifice Tormod's Crypt: Exile target player's graveyard.

Eerie Soultender

When Eerie Soultender enters, mill three cards. (Put the top three cards of your library into your graveyard.)
{4}{B}, Exile Eerie Soultender from your graveyard: Return another target creature card from your graveyard to your hand.

Carrion Grub

Carrion Grub gets +X/+0, where X is the greatest power among creature cards in your graveyard.
When Carrion Grub enters, mill four cards. (Put the top four cards of your library into your graveyard.)

Cemetery Recruitment

Return target creature card from your graveyard to your hand. If it's a Zombie card, draw a card.

Exhume

Each player puts a creature card from their graveyard onto the battlefield.

Mindwrack Harpy

Flying
At the beginning of combat on your turn, each player mills three cards.

Sinister Starfish

{T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Call to the Netherworld

Return target black creature card from your graveyard to your hand.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Phyrexian Rager

When Phyrexian Rager enters, you draw a card and you lose 1 life.

Nihil Spellbomb

{T}, Sacrifice Nihil Spellbomb: Exile target player's graveyard.
When Nihil Spellbomb is put into a graveyard from the battlefield, you may pay {B}. If you do, draw a card.

Gurmag Angler

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)

Swamp

Scrapwork Rager

When Scrapwork Rager enters, you draw a card and you lose 1 life.
Unearth {3}{B} ({3}{B}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Tendrils of Corruption

Tendrils of Corruption deals X damage to target creature and you gain X life, where X is the number of Swamps you control.

Ossuary Rats

When Ossuary Rats enters, it deals X damage to target creature or planeswalker an opponent controls, where X is the number of creature cards in your graveyard.

Tormod's Cryptkeeper

Vigilance
{T}, Sacrifice Tormod's Cryptkeeper: Exile target player's graveyard.

Shriekhorn

Shriekhorn enters with three charge counters on it.
{T}, Remove a charge counter from Shriekhorn: Target player mills two cards.

Writhing Necromass

This spell costs {1} less to cast for each creature card in your graveyard.
Deathtouch

Mephitic Vapors

All creatures get -1/-1 until end of turn.
Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)

Casting of Bones

Enchant creature
When enchanted creature dies, draw three cards, then discard one of them.

Summon Undead

You may mill three cards. Then return a creature card from your graveyard to the battlefield. (To mill a card, put the top card of your library into your graveyard.)

Dig Up the Body

Casualty 1 (As you cast this spell, you may sacrifice a creature with power 1 or greater. When you do, copy this spell.)
Mill two cards, then you may return a creature card from your graveyard to your hand. (To mill a card, put the top card of your library into your graveyard.)

Rotfeaster Maggot

When Rotfeaster Maggot enters, exile target creature card from a graveyard. You gain life equal to that card's toughness.

Wailing Ghoul

When Wailing Ghoul enters, mill two cards. (Put the top two cards of your library into your graveyard.)

Ghoulcaller's Bell

Stinkweed Imp

Flying
Whenever Stinkweed Imp deals combat damage to a creature, destroy that creature.
Dredge 5 (If you would draw a card, you may mill five cards instead. If you do, return this card from your graveyard to your hand.)

Ulamog's Crusher

Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)
Ulamog's Crusher attacks each combat if able.

Witch's Cottage

({T}: Add {B}.)
Witch's Cottage enters tapped unless you control three or more other Swamps.
When Witch's Cottage enters untapped, you may put target creature card from your graveyard on top of your library.

Commander's Sphere

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

Tocasia's Dig Site

{T}: Add {C}.
{3}, {T}: Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Troll of Khazad-dûm

Troll of Khazad-dûm can't be blocked except by three or more creatures.
Swampcycling {1} ({1}, Discard this card: Search your library for a Swamp card, reveal it, put it into your hand, then shuffle.)

Dross Golem

Affinity for Swamps (This spell costs {1} less to cast for each Swamp you control.)
Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Gorging Vulture

Flying
When Gorging Vulture enters, mill four cards. You gain 1 life for each creature card milled this way. (To mill four cards, put the top four cards of your library into your graveyard.)

Arcane Signet

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

Morgue Thrull

Sacrifice Morgue Thrull: Mill three cards.

Lotleth Giant

Undergrowth — When Lotleth Giant enters, it deals 1 damage to target opponent for each creature card in your graveyard.

Bone Shards

As an additional cost to cast this spell, sacrifice a creature or discard a card.
Destroy target creature or planeswalker.