Possible swaps

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

Treasure

{T}, Sacrifice this token: Add one mana of any color.

Songs of the Damned

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

Slavering Nulls

Whenever this creature deals combat damage to a player, if you control a Swamp, you may have that player discard a card.

Stinging Study

You draw X cards and you lose X life, where X is the mana value of a commander you own on the battlefield or in the command zone.

Gempalm Polluter

Cycling {B}{B} ({B}{B}, Discard this card: Draw a card.)
When you cycle this card, you may have target player lose life equal to the number of Zombies on the battlefield.

Getting

Carrion Feeder

This creature can't block.
Sacrifice a creature: Put a +1/+1 counter on this creature.

Have

Hive of the Eye Tyrant

If you control two or more other lands, this land enters tapped.
{T}: Add {B}.
{3}{B}: Until end of turn, this land becomes a 3/3 black Beholder creature with menace and "Whenever this creature attacks, exile target card from defending player's graveyard." It's still a land.

Corpse Harvester

{1}{B}, {T}, Sacrifice a creature: Search your library for a Zombie card and a Swamp card, reveal them, put them into your hand, then shuffle.

Rush of Vitality

Target creature gets +1/+0 and gains lifelink and indestructible until end of turn. (Damage dealt by that creature also causes its controller to gain that much life, and it can't be destroyed by damage or effects that say "destroy.")

Command Tower

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

Blood Crypt

({T}: Add {B} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Dark Ritual

Undying Evil

Target creature gains undying until end of turn. (When it dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Mountain

Pontiff of Blight

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Other creatures you control have extort. (If a creature has multiple instances of extort, each triggers separately.)

Eyes of the Beholder

Target creature gets -11/-11 until end of turn.

Blood Money

Destroy all creatures. For each nontoken creature destroyed this way, you create a tapped Treasure token.

Mortuary Mire

This land enters tapped.
When this land enters, you may put target creature card from your graveyard on top of your library.
{T}: Add {B}.

Sword of War and Peace

Equipped creature gets +2/+2 and has protection from red and from white.
Whenever equipped creature deals combat damage to a player, this Equipment deals damage to that player equal to the number of cards in their hand and you gain 1 life for each card in your hand.
Equip {2}

Swift End

Destroy target creature or planeswalker. You lose 2 life. (Then exile this card. You may cast the creature later from exile.)

Murderous Rider

Lifelink
When this creature dies, put it on the bottom of its owner's library.

Murderous Rider // Swift End

Swamp

Thought Vessel

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

Fell Mire

As this land enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {B}.

Fell the Profane

Fell the Profane // Fell Mire

Parasitic Impetus

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, its controller loses 2 life and you gain 2 life.

Don't Have

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.

Grave Upheaval

Put target creature card from a graveyard onto the battlefield under your control. It gains haste.
Basic landcycling {2} ({2}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Runed Stalactite

Equipped creature gets +1/+1 and is every creature type.
Equip {2}

Necrotic Hex

Each player sacrifices six creatures of their choice. You create six tapped 2/2 black Zombie creature tokens.

Diabolic Servitude

When this enchantment enters, return target creature card from your graveyard to the battlefield.
When the creature put onto the battlefield with this enchantment dies, exile it and return this enchantment to its owner's hand.
When this enchantment leaves the battlefield, exile the creature put onto the battlefield with this enchantment.

Dread

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Whenever a creature deals damage to you, destroy it.
When Dread is put into a graveyard from anywhere, shuffle it into its owner's library.

Infernal Grasp

Destroy target creature. You lose 2 life.

Nether Traitor

Haste
Shadow (This creature can block or be blocked by only creatures with shadow.)
Whenever another creature is put into your graveyard from the battlefield, you may pay {B}. If you do, return this card from your graveyard to the battlefield.

Oubliette

When this enchantment enters, target creature phases out until this enchantment leaves the battlefield. Tap that creature as it phases in this way. (Auras and Equipment phase out with it. While permanents are phased out, they're treated as though they don't exist.)

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Night's Whisper

Vindictive Lich

When this creature dies, choose one or more. Each mode must target a different player.
• Target opponent sacrifices a creature of their choice.
• Target opponent discards two cards.
• Target opponent loses 5 life.

Fling

As an additional cost to cast this spell, sacrifice a creature.
Fling deals damage equal to the sacrificed creature's power to any target.

Ghoulcaller's Chant

Choose one —
• Return target creature card from your graveyard to your hand.
• Return two target Zombie cards from your graveyard to your hand.

Liliana's Mastery

Zombies you control get +1/+1.
When this enchantment enters, create two 2/2 black Zombie creature tokens.

Kaya's Ghostform

Enchant creature or planeswalker you control
When enchanted permanent dies or is put into exile, return that card to the battlefield under your control.

Cemetery Recruitment

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

Reaper's Talisman

Whenever equipped creature attacks, it gains deathtouch until end of turn.
Whenever equipped creature attacks alone, defending player loses 2 life and you gain 2 life.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Gift of Doom

Enchant creature
Enchanted creature has deathtouch and indestructible.
Morph—Sacrifice another creature. (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
As this Aura is turned face up, you may attach it to a creature.

Contaminated Bond

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Whenever enchanted creature attacks or blocks, its controller loses 3 life.

Jet Medallion

Black spells you cast cost {1} less to cast.

Charcoal Diamond

This artifact enters tapped.
{T}: Add {B}.

Terminate

Destroy target creature. It can't be regenerated.

Ghoulish Impetus

Enchant creature
Enchanted creature gets +1/+1, has deathtouch, and is goaded.
When enchanted creature dies, return this card to the battlefield at the beginning of the next end step.

Afterlife from the Loam

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
For each player, choose up to one target creature card in that player's graveyard. Put those cards onto the battlefield under your control. They're Zombies in addition to their other types.

Bedevil

Destroy target artifact, creature, or planeswalker.

Dreadhorde Butcher

Haste
Whenever this creature deals combat damage to a player or planeswalker, put a +1/+1 counter on this creature.
When this creature dies, it deals damage equal to its power to any target.

Vengeful Pharaoh

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)
Whenever combat damage is dealt to you or a planeswalker you control, if this card is in your graveyard, destroy target attacking creature, then put this card on top of your library.

Jagged Barrens

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {B} or {R}.

Soulless One

Soulless One's power and toughness are each equal to the number of Zombies on the battlefield plus the number of Zombie cards in all graveyards.

Haunted Ridge

This land enters tapped unless you control two or more other lands.
{T}: Add {B} or {R}.

Subversion

At the beginning of your upkeep, each opponent loses 1 life. You gain life equal to the life lost this way.

Murderous Cut

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

Haunted Fengraf

{T}: Add {C}.
{3}, {T}, Sacrifice this land: Return a creature card at random from your graveyard to your hand.

Hoarder's Greed

You lose 2 life and draw two cards, then clash with an opponent. If you win, repeat this process. (Each clashing player reveals the top card of their library, then puts that card on their choice of the top or bottom. A player wins if their card had a greater mana value.)

War's Toll

Whenever an opponent taps a land for mana, tap all lands that player controls.
If a creature an opponent controls attacks, all creatures that opponent controls attack if able.

Ob Nixilis, the Hate-Twisted

Whenever an opponent draws a card, Ob Nixilis deals 1 damage to that player.
−2: Destroy target creature. Its controller draws two cards.

Valgavoth, Harrower of Souls

Flying
Ward—Pay 2 life.
Whenever an opponent loses life for the first time during each of their turns, put a +1/+1 counter on Valgavoth and draw a card.

Dread Return

Return target creature card from your graveyard to the battlefield.
Flashback—Sacrifice three creatures. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Kederekt Parasite

Whenever an opponent draws a card, if you control a red permanent, you may have this creature deal 1 damage to that player.

Village Rites

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

Vile Rebirth

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

Undead Augur

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

Nettling Curse

Enchant creature
Whenever enchanted creature attacks or blocks, its controller loses 3 life.
{1}{R}: Enchanted creature attacks this turn if able.

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Bladewing, Deathless Tyrant

Flying, haste
Whenever Bladewing deals combat damage to a player or planeswalker, for each creature card in your graveyard, create a 2/2 black Zombie Knight creature token with menace.

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Filth

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
As long as this card is in your graveyard and you control a Swamp, creatures you control have swampwalk.

Sanguine Morass

This land enters tapped.
{T}: Add {B} or {R}.

Bloodsoaked Insight

This spell costs {1} less to cast for each 1 life your opponents have lost this turn.
Target opponent exiles the top three cards of their library. Until the end of your next turn, you may play those cards. If you cast a spell this way, mana of any type can be spent to cast it.

Bloodsoaked Insight // Sanguine Morass

Dread Summons

Each player mills X cards. For each creature card put into a graveyard this way, you create a tapped 2/2 black Zombie creature token. (To mill a card, a player puts the top card of their library into their graveyard.)

Shepherd of Rot

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

Mikaeus, the Unhallowed

Intimidate (This creature can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a Human deals damage to you, destroy it.
Other non-Human creatures you control get +1/+1 and have undying. (When a creature with undying dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Flare of Malice

You may sacrifice a nontoken black creature rather than pay this spell's mana cost.
Each opponent sacrifices a creature or planeswalker with the greatest mana value among creatures and planeswalkers they control.

Lord of the Undead

Other Zombie creatures get +1/+1.
{1}{B}, {T}: Return target Zombie card from your graveyard to your hand.

Fellwar Stone

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

Fevered Suspicion

Each opponent exiles cards from the top of their library until they exile a nonland card. You may cast any number of spells from among those nonland cards without paying their mana costs.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Crowded Crypt

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

Mind Swords

If you control a Swamp, you may sacrifice a creature rather than pay this spell's mana cost.
Each player exiles two cards from their hand.

Gray Merchant of Asphodel

When this creature 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.)

Cursed Mirror

{T}: Add {R}.
As this artifact enters, you may have it become a copy of any creature on the battlefield until end of turn, except it has haste.

Underworld Dreams

Whenever an opponent draws a card, this enchantment deals 1 damage to that player.

Enchanter's Bane

At the beginning of your end step, target enchantment deals damage equal to its mana value to its controller unless that player sacrifices it.

Nim Deathmantle

Equipped creature gets +2/+2, has intimidate, and is a black Zombie. (A creature with intimidate can't be blocked except by artifact creatures and/or creatures that share a color with it.)
Whenever a nontoken creature is put into your graveyard from the battlefield, you may pay {4}. If you do, return that card to the battlefield and attach this Equipment to it.
Equip {4}

Lost Monarch of Ifnir

Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
Other Zombies you control have afflict 3.
At the beginning of your second main phase, if a player was dealt combat damage by a Zombie this turn, mill three cards, then you may return a creature card from your graveyard to your hand.

Sidisi, Undead Vizier

Deathtouch
Exploit (When this creature enters, you may sacrifice a creature.)
When Sidisi exploits a creature, you may search your library for a card, put it into your hand, then shuffle.

Tainted Peak

{T}: Add {C}.
{T}: Add {B} or {R}. Activate only if you control a Swamp.

Fire Diamond

This artifact enters tapped.
{T}: Add {R}.

Defile

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

Coronation of Chaos

Up to three target creatures can't block this turn. Goad them. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

Crypt Ghast

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
Whenever you tap a Swamp for mana, add an additional {B}.

Draugr's Helm

When this Equipment enters, you may pay {2}{B}. If you do, create a 2/2 black Zombie Berserker creature token, then attach this Equipment to it.
Equipped creature gets +2/+2 and has menace. (It can't be blocked except by two or more creatures.)
Equip {4}