Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni, Undying Partisan.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

In Garruk's Wake

Destroy all creatures you don't control and all planeswalkers you don't control.

Noxious Gearhulk

Menace
When Noxious Gearhulk enters the battlefield, you may destroy another target creature. If a creature is destroyed this way, you gain life equal to its toughness.

Snuff Out

If you control a Swamp, you may pay 4 life rather than pay this spell's mana cost.
Destroy target nonblack creature. It can't be regenerated.

Unearth

Return target creature card with mana value 3 or less from your graveyard to the battlefield.
Cycling {2} ({2}, Discard this card: Draw a card.)

Gonti, Lord of Luxury

Deathtouch
When Gonti, Lord of Luxury enters the battlefield, look at the top four cards of target opponent's library, exile one of them face down, then put the rest on the bottom of that library in a random order. You may cast that card for as long as it remains exiled, and mana of any type can be spent to cast that spell.

Vivid Marsh

Vivid Marsh enters the battlefield tapped with two charge counters on it.
{T}: Add {B}.
{T}, Remove a charge counter from Vivid Marsh: Add one mana of any color.

Hive of the Eye Tyrant

If you control two or more other lands, Hive of the Eye Tyrant enters the battlefield tapped.
{T}: Add {B}.
{3}{B}: Until end of turn, Hive of the Eye Tyrant 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.

Blood on the Snow

Choose one —
• Destroy all creatures.
• Destroy all planeswalkers.
Then return a creature or planeswalker card with mana value X or less from your graveyard to the battlefield, where X is the amount of {S} spent to cast this spell. ({S} is mana from a snow source.)

Erebos, God of the Dead

Indestructible
As long as your devotion to black is less than five, Erebos isn't a creature. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)
Your opponents can't gain life.
{1}{B}, Pay 2 life: Draw a card.

Baleful Mastery

You may pay {1}{B} rather than pay this spell's mana cost.
If the {1}{B} cost was paid, an opponent draws a card.
Exile target creature or planeswalker.

Swamp

Fleshbag Marauder

When Fleshbag Marauder enters the battlefield, each player sacrifices a creature.

Bojuka Bog

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

Join the Dead

Target creature gets -5/-5 until end of turn.
Descend 4 — That creature gets -10/-10 until end of turn instead if there are four or more permanent cards in your graveyard.

Call to the Grave

At the beginning of each player's upkeep, that player sacrifices a non-Zombie creature.
At the beginning of the end step, if no creatures are on the battlefield, sacrifice Call to the Grave.

Damnation

Destroy all creatures. They can't be regenerated.

Butcher of Malakir

Flying
Whenever Butcher of Malakir or another creature you control dies, each opponent sacrifices a creature.

Plaguecrafter

When Plaguecrafter enters the battlefield, each player sacrifices a creature or planeswalker. Each player who can't discards a card.

Ravenous Chupacabra

When Ravenous Chupacabra enters the battlefield, destroy target creature an opponent controls.

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

Witch's Cottage

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

Soul Shatter

Each opponent sacrifices a creature or planeswalker with the highest mana value among creatures and planeswalkers they control.

Sheoldred, Whispering One

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
At the beginning of your upkeep, return target creature card from your graveyard to the battlefield.
At the beginning of each opponent's upkeep, that player sacrifices a creature.

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

Changeling Outcast

Changeling (This card is every creature type.)
Changeling Outcast can't block and can't be blocked.

Infernal Grasp

Destroy target creature. You lose 2 life.

Leechridden Swamp

({T}: Add {B}.)
Leechridden Swamp enters the battlefield tapped.
{B}, {T}: Each opponent loses 1 life. Activate only if you control two or more black permanents.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Check for Traps

Target opponent reveals their hand. You choose a nonland card from it. Exile that card. If an instant card or a card with flash is exiled this way, they lose 1 life. Otherwise, you lose 1 life.

Go for the Throat

Hagra Broodpit

Hagra Broodpit enters the battlefield tapped.
{T}: Add {B}.

Hagra Mauling

This spell costs {1} less to cast if an opponent controls no basic lands.
Destroy target creature.

Hagra Mauling // Hagra Broodpit

Diabolic Intent

As an additional cost to cast this spell, sacrifice a creature.
Search your library for a card, put that card into your hand, then shuffle.

Shadows' Verdict

Exile all creatures and planeswalkers with mana value 3 or less from the battlefield and all creature and planeswalker cards with mana value 3 or less from all graveyards.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Defile

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

Massacre Wurm

When Massacre Wurm enters the battlefield, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

March of Wretched Sorrow

As an additional cost to cast this spell, you may exile any number of black cards from your hand. This spell costs {2} less to cast for each card exiled this way.
March of Wretched Sorrow deals X damage to target creature or planeswalker and you gain X life.

Gray Merchant of Asphodel

When Gray Merchant of Asphodel enters the battlefield, 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.)

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Phyrexian Obliterator

Trample
Whenever a source deals damage to Phyrexian Obliterator, that source's controller sacrifices that many permanents.

Field of Ruin

{T}: Add {C}.
{2}, {T}, Sacrifice Field of Ruin: Destroy target nonbasic land an opponent controls. Each player searches their library for a basic land card, puts it onto the battlefield, then shuffles.

Invoke Despair

Target opponent sacrifices a creature. If they can't, they lose 2 life and you draw a card. Then repeat this process for an enchantment and a planeswalker.

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}.

Dauthi Voidwalker

Shadow (This creature can block or be blocked by only creatures with shadow.)
If a card would be put into an opponent's graveyard from anywhere, instead exile it with a void counter on it.
{T}, Sacrifice Dauthi Voidwalker: Choose an exiled card an opponent owns with a void counter on it. You may play it this turn without paying its mana cost.

Pithing Needle

As Pithing Needle enters the battlefield, choose a card name.
Activated abilities of sources with the chosen name can't be activated unless they're mana abilities.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.