Sulfuric Vortex

At the beginning of each player's upkeep, Sulfuric Vortex deals 2 damage to that player.
If a player would gain life, that player gains no life instead.

Powerbalance

Whenever an opponent casts a spell, you may reveal the top card of your library. If you do, you may cast that card without paying its mana cost if the two spells have the same mana value.

Pain Magnification

Whenever an opponent is dealt 3 or more damage by a single source, that player discards a card.

Jet Medallion

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

Wound Reflection

At the beginning of each end step, each opponent loses life equal to the life they lost this turn. (Damage causes loss of life.)

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Obliterate

This spell can't be countered.
Destroy all artifacts, creatures, and lands. They can't be regenerated.

Spiteful Prankster

As long as it's your turn, Spiteful Prankster has first strike.
Whenever another creature dies, Spiteful Prankster deals 1 damage to target player or planeswalker.

Rakdos Locket

{T}: Add {B} or {R}.
{B/R}{B/R}{B/R}{B/R}, {T}, Sacrifice Rakdos Locket: Draw two cards.

Rakdos Signet

Protection Racket

At the beginning of your upkeep, repeat the following process for each opponent in turn order. Reveal the top card of your library. That player may pay life equal to that card's mana value. If they do, exile that card. Otherwise, put it into your hand.

Polluted Bonds

Whenever a land enters the battlefield under an opponent's control, that player loses 2 life and you gain 2 life.

Spreading Plague

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

Bloodchief Ascension

At the beginning of each end step, if an opponent lost 2 or more life this turn, you may put a quest counter on Bloodchief Ascension. (Damage causes loss of life.)
Whenever a card is put into an opponent's graveyard from anywhere, if Bloodchief Ascension has three or more quest counters on it, you may have that player lose 2 life. If you do, you gain 2 life.

Fellwar Stone

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

Ankh of Mishra

Whenever a land enters the battlefield, Ankh of Mishra deals 2 damage to that land's controller.

Spellshock

Whenever a player casts a spell, Spellshock deals 2 damage to that player.

Worldfire

Exile all permanents. Exile all cards from all hands and graveyards. Each player's life total becomes 1.

Toxic Deluge

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

Heartless Hidetsugu

{T}: Heartless Hidetsugu deals damage to each player equal to half that player's life total, rounded down.

Chandra, Awakened Inferno

This spell can't be countered.
+2: Each opponent gets an emblem with "At the beginning of your upkeep, this emblem deals 1 damage to you."
−3: Chandra, Awakened Inferno deals 3 damage to each non-Elemental creature.
−X: Chandra, Awakened Inferno deals X damage to target creature or planeswalker. If a permanent dealt damage this way would die this turn, exile it instead.

Jokulhaups

Destroy all artifacts, creatures, and lands. They can't be regenerated.

Zo-Zu the Punisher

Whenever a land enters the battlefield, Zo-Zu the Punisher deals 2 damage to that land's controller.

Smallpox

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

Mogis, God of Slaughter

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of each opponent's upkeep, Mogis deals 2 damage to that player unless they sacrifice a creature.

Aurora of Emrakul

Flying, deathtouch
Whenever Aurora of Emrakul attacks, each opponent loses 3 life.

Cryptolith Fragment

Cryptolith Fragment enters the battlefield tapped.
{T}: Add one mana of any color. Each player loses 1 life.
At the beginning of your upkeep, if each player has 10 or less life, transform Cryptolith Fragment.

Cryptolith Fragment // Aurora of Emrakul

Fire Diamond

Fire Diamond enters the battlefield tapped.
{T}: Add {R}.

Doom Blade

Burning Sands

Whenever a creature dies, that creature's controller sacrifices a land.

Swamp

Sol Ring

Liquimetal Torque

{T}: Add {C}.
{T}: Target nonland permanent becomes an artifact in addition to its other types until end of turn.

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.

Blood Moon

Altar of the Pantheon

Your devotion to each color and each combination of colors is increased by one.
{T}: Add one mana of any color. If you control a God, a Demigod, or a legendary enchantment, you gain 1 life.

Rix Maadi, Dungeon Palace

{T}: Add {C}.
{1}{B}{R}, {T}: Each player discards a card. Activate only as a sorcery.

Rug of Smothering

Flying
Whenever a player casts a spell, they lose 1 life for each spell they've cast this turn.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Phyrexian Arena

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

Doomwake Giant

Constellation — Whenever Doomwake Giant or another enchantment enters the battlefield under your control, creatures your opponents control get -1/-1 until end of turn.

Underworld Dreams

Whenever an opponent draws a card, Underworld Dreams deals 1 damage to that player.

Roiling Vortex

At the beginning of each player's upkeep, Roiling Vortex deals 1 damage to them.
Whenever a player casts a spell, if no mana was spent to cast that spell, Roiling Vortex deals 5 damage to that player.
{R}: Your opponents can't gain life this turn.

Arcane Signet

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

Wildfire

Each player sacrifices four lands. Wildfire deals 4 damage to each creature.

Dark Ritual

Kroxa, Titan of Death's Hunger

When Kroxa enters the battlefield, sacrifice it unless it escaped.
Whenever Kroxa enters the battlefield or attacks, each opponent discards a card, then each opponent who didn't discard a nonland card this way loses 3 life.
Escape—{B}{B}{R}{R}, Exile five other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Court of Ambition

When Court of Ambition enters the battlefield, you become the monarch.
At the beginning of your upkeep, each opponent loses 3 life unless they discard a card. If you're the monarch, instead each opponent loses 6 life unless they discard two cards.

Descent into Avernus

At the beginning of your upkeep, put two descent counters on Descent into Avernus. Then each player creates X Treasure tokens and Descent into Avernus deals X damage to each player, where X is the number of descent counters on Descent into Avernus.

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.

Ruination

Everlasting Torment

Players can't gain life.
Damage can't be prevented.
All damage is dealt as though its source had wither. (A source with wither deals damage to creatures in the form of -1/-1 counters.)

Aether Flash

Whenever a creature enters the battlefield, Aether Flash deals 2 damage to it.

Tainted Aether

Whenever a creature enters the battlefield, its controller sacrifices a creature or land.

Fate Unraveler

Whenever an opponent draws a card, Fate Unraveler deals 1 damage to that player.

Mountain

Kaervek, the Spiteful

Soul Shatter

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

Charcoal Diamond

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

Spiteful Banditry

When Spiteful Banditry enters the battlefield, it deals X damage to each creature.
Whenever one or more creatures your opponents control die, you create a Treasure token. This ability triggers only once each turn.

Painful Quandary

Whenever an opponent casts a spell, that player loses 5 life unless they discard a card.

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.

Cloud Key

As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Massacre

If an opponent controls a Plains and you control a Swamp, you may cast this spell without paying its mana cost.
All creatures get -2/-2 until end of turn.

Plaguecrafter

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

Shivan Gorge

{T}: Add {C}.
{2}{R}, {T}: Shivan Gorge deals 1 damage to each opponent.

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Grim Guardian

Constellation — Whenever Grim Guardian or another enchantment enters the battlefield under your control, each opponent loses 1 life.

Vandalblast

Destroy target artifact you don't control.
Overload {4}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Ruby Medallion

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

No Mercy

Whenever a creature deals damage to you, destroy it.

Price of Progress

Price of Progress deals damage to each player equal to twice the number of nonbasic lands that player controls.

Devastation

Mind Stone

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

Decree of Annihilation

Exile all artifacts, creatures, and lands from the battlefield, all cards from all graveyards, and all cards from all hands.
Cycling {5}{R}{R} ({5}{R}{R}, Discard this card: Draw a card.)
When you cycle Decree of Annihilation, destroy all lands.

Lethal Vapors

Whenever a creature enters the battlefield, destroy it.
{0}: Destroy Lethal Vapors. You skip your next turn. Any player may activate this ability.

Talisman of Indulgence

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