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."

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Springleaf Drum

{T}, Tap an untapped creature you control: Add one mana of any color.

Thieves' Auction

Exile all nontoken permanents. Starting with you, each player chooses one of the exiled cards and puts it onto the battlefield tapped under their control. Repeat this process until all cards exiled this way have been chosen.

Brand

Gain control of all permanents you own. (This effect lasts indefinitely.)
Cycling {2} ({2}, Discard this card: Draw a card.)

Fiery Emancipation

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

Valakut Stoneforge

Valakut Stoneforge enters tapped.
{T}: Add {R}.

Valakut Awakening

Put any number of cards from your hand on the bottom of your library, then draw that many cards plus one.

Valakut Awakening // Valakut Stoneforge

Magus of the Moon

Gimli of the Glittering Caves

Double strike
Whenever another legendary creature you control enters, put a +1/+1 counter on Gimli of the Glittering Caves.
Whenever Gimli deals combat damage to a player, create a Treasure token.

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.

Stranglehold

Your opponents can't search libraries.
If an opponent would begin an extra turn, that player skips that turn 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.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Outpost Siege

As Outpost Siege enters, choose Khans or Dragons.
• Khans — At the beginning of your upkeep, exile the top card of your library. Until end of turn, you may play that card.
• Dragons — Whenever a creature you control leaves the battlefield, Outpost Siege deals 1 damage to any target.

Magus of the Wheel

{1}{R}, {T}, Sacrifice Magus of the Wheel: Each player discards their hand, then draws seven cards.

Stolen Strategy

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.

Kher Keep

{T}: Add {C}.
{1}{R}, {T}: Create a 0/1 red Kobold creature token named Kobolds of Kher Keep.

Sol Ring

War Room

{T}: Add {C}.
{3}, {T}, Pay life equal to the number of colors in your commanders' color identity: Draw a card.

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.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Arcane Signet

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Warp World

Each player shuffles all permanents they own into their library, then reveals that many cards from the top of their library. Each player puts all artifact, creature, and land cards revealed this way onto the battlefield, then does the same for enchantment cards, then puts all cards revealed this way that weren't put onto the battlefield on the bottom of their library.

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.

Worldfire

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

Possibility Storm

Whenever a player casts a spell from their hand, that player exiles it, then exiles cards from the top of their library until they exile a card that shares a card type with it. That player may cast that card without paying its mana cost. Then they put all cards exiled with Possibility Storm on the bottom of their library in a random order.

Treasure Nabber

Whenever an opponent taps an artifact for mana, gain control of that artifact until the end of your next turn.

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}.

Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random. Its controller mills that many cards, then exiles cards from the top of their library until they exile a nonland card with a different name than that spell. They may cast that card without paying its mana cost. Then they put the exiled cards on the bottom of their library in a random order.

Scrambleverse

For each nonland permanent, choose a player at random. Then each player gains control of each permanent for which they were chosen. Untap those permanents.

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Chain Reaction

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

Witty Roastmaster

Alliance — Whenever another creature you control enters, Witty Roastmaster deals 1 damage to each opponent.

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.)

Jaya, Venerated Firemage

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.
−2: Jaya, Venerated Firemage deals 2 damage to any target.

Blood Moon

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Altar of the Brood

Whenever another permanent you control enters, each opponent mills a card.

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

Tome of Legends

Tome of Legends enters with a page counter on it.
Whenever your commander enters or attacks, put a page counter on Tome of Legends.
{1}, {T}, Remove a page counter from Tome of Legends: Draw a card.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Iron Myr

Terror of the Peaks

Flying
Spells your opponents cast that target Terror of the Peaks cost an additional 3 life to cast.
Whenever another creature you control enters, Terror of the Peaks deals damage equal to that creature's power to any target.

Relic of Legends

{T}: Add one mana of any color.
Tap an untapped legendary creature you control: Add one mana of any color.

Honor-Worn Shaku

{T}: Add {C}.
Tap an untapped legendary permanent you control: Untap Honor-Worn Shaku.

Guff Rewrites History

For each player, choose target nonenchantment, nonland permanent that player controls. Those permanents' owners shuffle them into their libraries. Each player who controlled one of those permanents exiles cards from the top of their library until they exile a nonland card, then puts the rest on the bottom of their library in a random order. Each player may cast the nonland card they exiled without paying its mana cost.

Mechanized Warfare

If a red or artifact source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 1 instead.

Koth of the Hammer

+1: Untap target Mountain. It becomes a 4/4 red Elemental creature until end of turn. It's still a land.
−2: Add {R} for each Mountain you control.
−5: You get an emblem with "Mountains you control have '{T}: This land deals 1 damage to any target.'"

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.

Rose Room Treasurer

Alliance — Whenever another creature you control enters, create a Treasure token if this is the first or second time this ability has resolved this turn. Otherwise, you may pay {X}. When you do, Rose Room Treasurer deals X damage to any target.

Wild Magic Surge

Destroy target permanent an opponent controls. Its controller reveals cards from the top of their library until they reveal a permanent card that shares a card type with that permanent. They put that card onto the battlefield and the rest on the bottom of their library in a random order.

Mind Stone

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

Mines of Moria

Mines of Moria enters tapped unless you control a legendary creature.
{T}: Add {R}.
{3}{R}, {T}, Exile three cards from your graveyard: Create two Treasure tokens.

Mana Geyser

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

Confusion in the Ranks

Whenever an artifact, creature, or enchantment enters, its controller chooses target permanent another player controls that shares a card type with it. Exchange control of those permanents.

Wheel of Misfortune

Each player secretly chooses a number 0 or greater, then all players reveal those numbers simultaneously and determine the highest and lowest numbers revealed this way. Wheel of Misfortune deals damage equal to the highest number to each player who chose that number. Each player who didn't choose the lowest number discards their hand, then draws seven cards.

City on Fire

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Humble Defector

{T}: Draw two cards. Target opponent gains control of Humble Defector. Activate only during your turn.

Blasphemous Act

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

Genesis Chamber

Whenever a nontoken creature enters, if Genesis Chamber is untapped, that creature's controller creates a 1/1 colorless Myr artifact creature token.

Mirror March

Whenever a nontoken creature you control enters, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Pandemonium

Whenever a creature enters, that creature's controller may have it deal damage equal to its power to any target of their choice.

Solemn Simulacrum

When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.
When this creature dies, you may draw a card.

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.)