Obsidian Fireheart

{1}{R}{R}: Put a blaze counter on target land without a blaze counter on it. For as long as that land has a blaze counter on it, it has "At the beginning of your upkeep, this land deals 1 damage to you." (The land continues to burn after Obsidian Fireheart has left the battlefield.)

Fortune Thief

Damage that would reduce your life total to less than 1 reduces it to 1 instead.
Morph {R}{R} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Acidic Soil

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

Ruby Medallion

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

Volcanic Fallout

This spell can't be countered.
Volcanic Fallout deals 2 damage to each creature and each player.

Meekstone

Creatures with power 3 or greater don't untap during their controllers' untap steps.

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.

Zo-Zu the Punisher

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

Rampaging Ferocidon

Menace
Players can't gain life.
Whenever another creature enters, Rampaging Ferocidon deals 1 damage to that creature's controller.

Immolation Shaman

Whenever an opponent activates an ability of an artifact, creature, or land that isn't a mana ability, Immolation Shaman deals 1 damage to that player.
{3}{R}{R}: Immolation Shaman gets +3/+3 and gains menace until end of turn.

Shivan Gorge

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

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}.

Flame Rift

Flame Rift deals 4 damage to each player.

Kazuul, Tyrant of the Cliffs

Whenever a creature an opponent controls attacks, if you're the defending player, create a 3/3 red Ogre creature token unless that creature's controller pays {3}.

Akki Blizzard-Herder

When Akki Blizzard-Herder dies, each player sacrifices a land.

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.)

Viashino Heretic

{1}{R}, {T}: Destroy target artifact. Viashino Heretic deals damage to that artifact's controller equal to the artifact's mana value.

Smoke

Players can't untap more than one creature during their untap steps.

Ankh of Mishra

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

Reforge the Soul

Each player discards their hand, then draws seven cards.
Miracle {1}{R} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Fire Diamond

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

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.

Sol Ring

Ghirapur Orrery

Each player may play an additional land on each of their turns.
At the beginning of each player's upkeep, if that player has no cards in hand, that player draws three cards.

Spellshock

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

Sun Droplet

Whenever you're dealt damage, put that many charge counters on Sun Droplet.
At the beginning of each upkeep, you may remove a charge counter from Sun Droplet. If you do, you gain 1 life.

Smoldering Crater

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

Tectonic Instability

Whenever a land enters, tap all lands its controller controls.

Seething Song

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.

Dictate of the Twin Gods

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

Forgotten Cave

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

Firebrand Archer

Whenever you cast a noncreature spell, Firebrand Archer deals 1 damage to each opponent.

Sin Prodder

Menace
At the beginning of your upkeep, reveal the top card of your library. Any opponent may have you put that card into your graveyard. If a player does, Sin Prodder deals damage to that player equal to that card's mana value. Otherwise, put that card into your hand.

War Elemental

When War Elemental enters, sacrifice it unless an opponent was dealt damage this turn.
Whenever an opponent is dealt damage, put that many +1/+1 counters on War Elemental.

Manabarbs

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

Earthquake

Earthquake deals X damage to each creature without flying and each player.

Dismissive Pyromancer

{R}, {T}, Discard a card: Draw a card.
{2}{R}, {T}, Sacrifice Dismissive Pyromancer: It deals 4 damage to target creature.

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.

Burning Earth

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

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.")

Stigma Lasher

Wither (This deals damage to creatures in the form of -1/-1 counters.)
Whenever Stigma Lasher deals damage to a player, that player can't gain life for the rest of the game.

Neheb, the Eternal

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

Darksteel Ingot

Indestructible (Effects that say "destroy" don't destroy this artifact.)
{T}: Add one mana of any color.

Price of Progress

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

Impatience

At the beginning of each player's end step, if that player didn't cast a spell this turn, Impatience deals 2 damage to that player.

Keldon Firebombers

When Keldon Firebombers enters, each player sacrifices all lands they control except for three.

Burnished Hart

{3}, Sacrifice Burnished Hart: Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

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.

Ramunap Ruins

{T}: Add {C}.
{T}, Pay 1 life: Add {R}.
{2}{R}{R}, {T}, Sacrifice a Desert: Ramunap Ruins deals 2 damage to each opponent.

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

Mana Geyser

Add {R} for each tapped land your opponents control.

Embermaw Hellion

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
If another red source you control would deal damage to a permanent or player, it deals that much damage plus 1 to that permanent or player instead.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Ruination

Harsh Mentor

Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, Harsh Mentor deals 2 damage to that player.

Pristine Talisman

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Stoneshaker Shaman

At the beginning of each player's end step, that player sacrifices an untapped land.

Desert of the Fervent

Desert of the Fervent enters tapped.
{T}: Add {R}.
Cycling {1}{R} ({1}{R}, Discard this card: Draw a card.)

Heartless Hidetsugu

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

Pyromancer's Goggles

{T}: Add {R}. When that mana is spent to cast a red instant or sorcery spell, copy that spell and you may choose new targets for the copy.

Glacial Chasm

Cumulative upkeep—Pay 2 life. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When Glacial Chasm enters, sacrifice a land.
Creatures you control can't attack.
Prevent all damage that would be dealt to you.

Scab-Clan Berserker

Haste
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever an opponent casts a noncreature spell, if Scab-Clan Berserker is renowned, Scab-Clan Berserker deals 2 damage to that player.

Blasphemous Act

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

Molten Psyche

Each player shuffles the cards from their hand into their library, then draws that many cards.
Metalcraft — If you control three or more artifacts, Molten Psyche deals damage to each opponent equal to the number of cards that player has drawn this turn.

Iron Myr

Tunnel Ignus

Whenever a land enters under an opponent's control, if that player had another land enter the battlefield under their control this turn, Tunnel Ignus deals 3 damage to that player.

Khorvath's Fury

For each player, choose friend or foe. Each friend discards all cards from their hand, then draws that many cards plus one. Khorvath's Fury deals damage to each foe equal to the number of cards in their hand.

Mountain

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

Pyrostatic Pillar

Whenever a player casts a spell with mana value 3 or less, Pyrostatic Pillar deals 2 damage to that player.