Plague of Vermin

Starting with you, each player may pay any amount of life. Repeat this process until no one pays life. Each player creates a 1/1 black Rat creature token for each 1 life they paid this way.

Endemic Plague

As an additional cost to cast this spell, sacrifice a creature.
Destroy all creatures that share a creature type with the sacrificed creature. They can't be regenerated.

Curse of Death's Hold

Enchant player
Creatures enchanted player controls get -1/-1.

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.

Maga, Traitor to Mortals

Maga, Traitor to Mortals enters the battlefield with X +1/+1 counters on it.
When Maga enters the battlefield, target player loses life equal to the number of +1/+1 counters on it.

Each player loses a third of their life, then discards a third of the cards in their hand, then sacrifices a third of the creatures they control, then sacrifices a third of the lands they control. Round up each time.

Shauku, Endbringer

Flying
Shauku, Endbringer can't attack if there's another creature on the battlefield.
At the beginning of your upkeep, you lose 3 life.
{T}: Exile target creature and put a +1/+1 counter on Shauku.

Typhoid Rats

Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Swallowing Plague

Swallowing Plague deals X damage to target creature and you gain X life.

Spread the Sickness

Destroy target creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Plague Fiend

Whenever Plague Fiend deals combat damage to a creature, destroy that creature unless its controller pays {2}.

Larceny

Whenever a creature you control deals combat damage to a player, that player discards a card.

Plague Belcher

Menace
When Plague Belcher enters the battlefield, put two -1/-1 counters on target creature you control.
Whenever another Zombie you control dies, each opponent loses 1 life.

Grimoire of the Dead

{1}, {T}, Discard a card: Put a study counter on Grimoire of the Dead.
{T}, Remove three study counters from Grimoire of the Dead and sacrifice it: Put all creature cards from all graveyards onto the battlefield under your control. They're black Zombies in addition to their other colors and types.

Greed

Blowfly Infestation

Whenever a creature dies, if it had a -1/-1 counter on it, put a -1/-1 counter on target creature.

Crumbling Ashes

At the beginning of your upkeep, destroy target creature with a -1/-1 counter on it.

Skithiryx, the Blight Dragon

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{B}: Skithiryx, the Blight Dragon gains haste until end of turn.
{B}{B}: Regenerate Skithiryx.

Plague Dogs

When Plague Dogs dies, all creatures get -1/-1 until end of turn.
{2}, Sacrifice Plague Dogs: Draw a card.

Spreading Plague

Whenever a creature enters the battlefield, destroy all other creatures that share a color with it. They can't be regenerated.

Brainspoil

Destroy target creature that isn't enchanted. It can't be regenerated.
Transmute {1}{B}{B} ({1}{B}{B}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Fevered Convulsions

{2}{B}{B}: Put a -1/-1 counter on target creature.

Black Market

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

Engineered Plague

As Engineered Plague enters the battlefield, choose a creature type.
All creatures of the chosen type get -1/-1.

Plague Witch

{B}, {T}, Discard a card: Target creature gets -1/-1 until end of turn.

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.

Smallpox

Each player loses 1 life, discards a card, sacrifices a creature, then sacrifices a land.

No Mercy

Whenever a creature deals damage to you, destroy it.

Liliana of the Veil

+1: Each player discards a card.
−2: Target player sacrifices a creature.
−6: Separate all permanents target player controls into two piles. That player sacrifices all permanents in the pile of their choice.

Life's Finale

Destroy all creatures, then search target opponent's library for up to three creature cards and put them into their graveyard. Then that player shuffles.

Grave Pact

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

Pestilence Rats

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

Traveling Plague

Enchant creature
At the beginning of each upkeep, put a plague counter on Traveling Plague.
Enchanted creature gets -1/-1 for each plague counter on Traveling Plague.
When enchanted creature leaves the battlefield, that creature's controller returns Traveling Plague from its owner's graveyard to the battlefield.

Phyrexian Plaguelord

{T}, Sacrifice Phyrexian Plaguelord: Target creature gets -4/-4 until end of turn.
Sacrifice a creature: Target creature gets -1/-1 until end of turn.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Plaguecrafter

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

Sorin Markov

+2: Sorin Markov deals 2 damage to any target and you gain 2 life.
−3: Target opponent's life total becomes 10.
−7: You control target player during that player's next turn.

Reassembling Skeleton

{1}{B}: Return Reassembling Skeleton from your graveyard to the battlefield tapped.

Plague Wight

Whenever Plague Wight becomes blocked, each creature blocking it gets -1/-1 until end of turn.

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

Plagued Rusalka

{B}, Sacrifice a creature: Target creature gets -1/-1 until end of turn.

Despoil

Destroy target land. Its controller loses 2 life.

Plaguebearer

{X}{X}{B}: Destroy target nonblack creature with mana value X.

Hatred

As an additional cost to cast this spell, pay X life.
Target creature gets +X/+0 until end of turn.

Virulent Plague

Phyrexian Arena

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

Incremental Blight

Put a -1/-1 counter on target creature, two -1/-1 counters on another target creature, and three -1/-1 counters on a third target creature.

Gravecrawler

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

Death Cloud

Each player loses X life, discards X cards, sacrifices X creatures, then sacrifices X lands.

Krovikan Plague

Enchant non-Wall creature you control
When Krovikan Plague enters the battlefield, draw a card at the beginning of the next turn's upkeep.
Tap enchanted creature: Krovikan Plague deals 1 damage to any target. Put a -0/-1 counter on enchanted creature. Activate only if enchanted creature is untapped.

Infected Vermin

{2}{B}: Infected Vermin deals 1 damage to each creature and each player.
Threshold — {3}{B}: Infected Vermin deals 3 damage to each creature and each player. Activate only if seven or more cards are in your graveyard.

Swamp

Deathgreeter

Whenever another creature dies, you may gain 1 life.

Necroskitter

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever a creature an opponent controls with a -1/-1 counter on it dies, you may return that card to the battlefield under your control.

Pestilence Demon

Flying
{B}: Pestilence Demon deals 1 damage to each creature and each player.

Plague Myr

Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{T}: Add {C}.

Phyrexian Crusader

First strike, protection from red and from white
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Exsanguinate

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

Plague Spitter

At the beginning of your upkeep, Plague Spitter deals 1 damage to each creature and each player.
When Plague Spitter dies, it deals 1 damage to each creature and each player.

Contamination

At the beginning of your upkeep, sacrifice Contamination unless you sacrifice a creature.
If a land is tapped for mana, it produces {B} instead of any other type and amount.

Nettlevine Blight

Enchant creature or land
Enchanted permanent has "At the beginning of your end step, sacrifice this permanent and attach Nettlevine Blight to a creature or land you control."

Undercity Plague

Target player loses 1 life, discards a card, then sacrifices a permanent.
Cipher (Then you may exile this spell card encoded on a creature you control. Whenever that creature deals combat damage to a player, its controller may cast a copy of the encoded card without paying its mana cost.)

Pestilence

At the beginning of the end step, if no creatures are on the battlefield, sacrifice Pestilence.
{B}: Pestilence deals 1 damage to each creature and each player.

Liliana Vess

+1: Target player discards a card.
−2: Search your library for a card, then shuffle and put that card on top.
−8: Put all creature cards from all graveyards onto the battlefield under your control.

Plague Wind

Destroy all creatures you don't control. They can't be regenerated.

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to your devotion to that color. (Your devotion to a color is the number of mana symbols of that color in the mana costs of permanents you control.)

Dakmor Plague

Dakmor Plague deals 3 damage to each creature and each player.

Plague Engineer

Deathtouch
As Plague Engineer enters the battlefield, choose a creature type.
Creatures of the chosen type your opponents control get -1/-1.

Exotic Disease

Domain — Target player loses X life and you gain X life, where X is the number of basic land types among lands you control.

Disease Carriers

When Disease Carriers dies, target creature gets -2/-2 until end of turn.

Diseased Vermin

Whenever Diseased Vermin deals combat damage to a player, put an infection counter on it.
At the beginning of your upkeep, Diseased Vermin deals X damage to target opponent previously dealt damage by it, where X is the number of infection counters on it.

Plague Mare

Plague Mare can't be blocked by white creatures.
When Plague Mare enters the battlefield, creatures your opponents control get -1/-1 until end of turn.

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.

Plague Stinger

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Necrotic Plague

Enchant creature
Enchanted creature has "At the beginning of your upkeep, sacrifice this creature."
When enchanted creature dies, its controller chooses target creature one of their opponents controls. Return Necrotic Plague from its owner's graveyard to the battlefield attached to that creature.