Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

Burning Earth

Whenever a player taps a nonbasic land for mana, Burning Earth deals 1 damage to that player.

Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard Sokenzan, Crucible of Defiance: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Meteor Swarm

Meteor Swarm deals 8 damage divided as you choose among X target creatures and/or planeswalkers.

Shatterskull Charger

Kicker {2}
Trample, haste
If Shatterskull Charger was kicked, it enters with a +1/+1 counter on it.
At the beginning of your end step, if Shatterskull Charger doesn't have a +1/+1 counter on it, return it to its owner's hand.

Mana Clash

You and target opponent each flip a coin. Mana Clash deals 1 damage to each player whose coin comes up tails. Repeat this process until both players' coins come up heads on the same flip.

Thermo-Alchemist

Defender
{T}: Thermo-Alchemist deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Furnace of Rath

If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Chaos Maw

When Chaos Maw enters, it deals 3 damage to each other creature.

Flamebreak

Flamebreak deals 3 damage to each creature without flying and each player. Creatures dealt damage this way can't be regenerated this turn.

Invoke Calamity

You may cast up to two instant and/or sorcery spells with total mana value 6 or less from your graveyard and/or hand without paying their mana costs. If those spells would be put into your graveyard, exile them instead. Exile Invoke Calamity.

Pyrohemia

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

Smoldering Crater

Smoldering Crater enters tapped.
{T}: Add {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Mazemind Tome

{T}, Put a page counter on Mazemind Tome: Scry 1.
{2}, {T}, Put a page counter on Mazemind Tome: Draw a card.
When there are four or more page counters on Mazemind Tome, exile it. If you do, you gain 4 life.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Curse of Bloodletting

Enchant player
If a source would deal damage to enchanted player, it deals double that damage to that player instead.

Magus of the Moon

Nyx Lotus

Nyx Lotus enters tapped.
{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.)

Bonfire of the Damned

Bonfire of the Damned deals X damage to target player or planeswalker and each creature that player or that planeswalker's controller controls.
Miracle {X}{R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

Volt Charge

Volt Charge deals 3 damage to any target. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

Koth, Fire of Resistance

+2: Search your library for a basic Mountain card, reveal it, put it into your hand, then shuffle.
−3: Koth, Fire of Resistance deals damage to target creature equal to the number of Mountains you control.
−7: You get an emblem with "Whenever a Mountain you control enters, this emblem deals 4 damage to any target."

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Neheb, the Eternal

Afflict 3 (Whenever this creature becomes blocked, defending player loses 3 life.)
At the beginning of each of your postcombat main phases, add {R} for each 1 life your opponents have lost this turn.

Urabrask's Forge

At the beginning of combat on your turn, put an oil counter on Urabrask's Forge, then create an X/1 red Phyrexian Horror creature token with trample and haste, where X is the number of oil counters on Urabrask's Forge. Sacrifice that token at the beginning of the next end step.

Fire Diamond

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

Sawblade Scamp

Haste
Whenever you cast a noncreature spell, put an oil counter on Sawblade Scamp.
{T}, Remove an oil counter from Sawblade Scamp: It deals 1 damage to each opponent.

Explosive Singularity

As an additional cost to cast this spell, you may tap any number of untapped creatures you control. This spell costs {1} less to cast for each creature tapped this way.
Explosive Singularity deals 10 damage to any target.

Sol Ring

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: Grim Lavamancer deals 2 damage to any target.

Dagger Caster

When Dagger Caster enters, it deals 1 damage to each opponent and 1 damage to each creature your opponents control.

Goblin Sharpshooter

Goblin Sharpshooter doesn't untap during your untap step.
Whenever a creature dies, untap Goblin Sharpshooter.
{T}: Goblin Sharpshooter deals 1 damage to any target.

Chandra's Ignition

Target creature you control deals damage equal to its power to each other creature and each opponent.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Acidic Soil

Acidic Soil deals damage to each player equal to the number of lands they control.

Browbeat

Any player may have Browbeat deal 5 damage to them. If no one does, target player draws three cards.

Combustible Gearhulk

First strike
When Combustible Gearhulk enters, target opponent may have you draw three cards. If the player doesn't, you mill three cards, then Combustible Gearhulk deals damage to that player equal to the total mana value of those cards.

Sundering Stroke

Sundering Stroke deals 7 damage divided as you choose among one, two, or three targets. If at least seven red mana was spent to cast this spell, instead Sundering Stroke deals 7 damage to each of those permanents and/or players.

Fanatic of Mogis

When Fanatic of Mogis enters, it deals damage to each opponent equal to your devotion to red. (Each {R} in the mana costs of permanents you control counts toward your devotion to red.)

Mountain

Kuldotha Cackler

Trample
Whenever Kuldotha Cackler attacks, it gets +X/+0 until end of turn, where X is the number of permanents you control with oil counters on them.

Magmatic Channeler

As long as there are four or more instant and/or sorcery cards in your graveyard, Magmatic Channeler gets +3/+1.
{T}, Discard a card: Exile the top two cards of your library, then choose one of them. You may play that card this turn.

Tears of Valakut

This spell can't be countered.
Tears of Valakut deals 5 damage to target creature with flying.

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Red Elemental Blast

Choose one —
• Counter target blue spell.
• Destroy target blue permanent.

Risk Factor

Target opponent may have Risk Factor deal 4 damage to them. If that player doesn't, you draw three cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Defiler of Instinct

First strike
As an additional cost to cast red permanent spells, you may pay 2 life. Those spells cost {R} less to cast if you paid life this way. This effect reduces only the amount of red mana you pay.
Whenever you cast a red permanent spell, Defiler of Instinct deals 1 damage to any target.

Heartless Hidetsugu

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

Valakut, the Molten Pinnacle

Valakut, the Molten Pinnacle enters tapped.
Whenever a Mountain you control enters, if you control at least five other Mountains, you may have Valakut, the Molten Pinnacle deal 3 damage to any target.
{T}: Add {R}.

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.

Skullcrack

Players can't gain life this turn. Damage can't be prevented this turn. Skullcrack deals 3 damage to target player or planeswalker.

Shivan Gorge

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

Runaway Steam-Kin

Whenever you cast a red spell, if Runaway Steam-Kin has fewer than three +1/+1 counters on it, put a +1/+1 counter on Runaway Steam-Kin.
Remove three +1/+1 counters from Runaway Steam-Kin: Add {R}{R}{R}.

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Basilisk Collar

Equipped creature has deathtouch and lifelink.
Equip {2}

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Fated Conflagration

Fated Conflagration deals 5 damage to target creature or planeswalker. If it's your turn, scry 2.

Repeating Barrage

Repeating Barrage deals 3 damage to any target.
Raid — {3}{R}{R}: Return Repeating Barrage from your graveyard to your hand. Activate only if you attacked this turn.

Blasphemous Act

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

Hazardous Blast

Hazardous Blast deals 1 damage to each creature your opponents control. Creatures your opponents control can't block this turn.

Star Compass

Star Compass enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Shrapnel Slinger

When Shrapnel Slinger enters, you may sacrifice a creature. When you do, destroy target artifact an opponent controls.

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Tectonic Reformation

Each land card in your hand has cycling {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Command the Storm

Command the Storm deals 5 damage to target creature.

Fall of the Titans

Surge {X}{R} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Fall of the Titans deals X damage to each of up to two targets.

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

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.

Burning Sun's Avatar

When Burning Sun's Avatar enters, it deals 3 damage to target opponent or planeswalker and 3 damage to up to one target creature.

Solphim, Mayhem Dominus

If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals double that damage to that player or permanent instead.
{1}{R/P}{R/P}, Discard two cards: Put an indestructible counter on Solphim, Mayhem Dominus. ({R/P} can be paid with either {R} or 2 life.)

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Ember Beast

Mind Stone

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

Myriad Landscape

Myriad Landscape enters tapped.
{T}: Add {C}.
{2}, {T}, Sacrifice Myriad Landscape: Search your library for up to two basic land cards that share a land type, put them onto the battlefield tapped, then shuffle.

Price of Progress

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Commander's Sphere

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

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Repercussion

Whenever a creature is dealt damage, Repercussion deals that much damage to that creature's controller.

Chandra, Pyrogenius

+2: Chandra, Pyrogenius deals 2 damage to each opponent.
−3: Chandra, Pyrogenius deals 4 damage to target creature.
−10: Chandra, Pyrogenius deals 6 damage to target player or planeswalker and each creature that player or that planeswalker's controller controls.