Leyline of Combustion

If Leyline of Combustion is in your opening hand, you may begin the game with it on the battlefield.
Whenever you and/or at least one permanent you control becomes the target of a spell or ability an opponent controls, Leyline of Combustion deals 2 damage to that player.

Forest

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.

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.

Arcane Signet

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

Fire Servant

If a red instant or sorcery spell you control would deal damage, it deals double that damage instead.

Llanowar Elves

Shadow in the Warp

The first creature spell you cast each turn costs {2} less to cast.
Whenever an opponent casts their first noncreature spell each turn, Shadow in the Warp deals 2 damage to that player.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Decimate

Destroy target artifact, target creature, target enchantment, and target land. (You can't cast this spell unless you have legal choices for all its targets.)

Brotherhood's End

Choose one —
• Brotherhood's End deals 3 damage to each creature and each planeswalker.
• Destroy all artifacts with mana value 3 or less.

Regrowth

Return target card from your graveyard to your hand.

Pyromancer's Gauntlet

If a red instant or sorcery spell you control or a red planeswalker you control would deal damage to a permanent or player, it deals that much damage plus 2 to that permanent or player instead.

Breath of Darigaaz

Kicker {2} (You may pay an additional {2} as you cast this spell.)
Breath of Darigaaz deals 1 damage to each creature without flying and each player. If this spell was kicked, it deals 4 damage to each creature without flying and each player instead.

Unexpected Windfall

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Goblin Anarchomancer

Each spell you cast that's red or green costs {1} less to cast.

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Delayed Blast Fireball

Delayed Blast Fireball deals 2 damage to each opponent and each creature they control. If this spell was cast from exile, it deals 5 damage to each opponent and each creature they control instead.
Foretell {4}{R}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Acidic Soil

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

Firebrand Archer

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

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.

Sizzle

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.

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.)

Gratuitous Violence

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

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.

Tectonic Giant

Whenever Tectonic Giant attacks or becomes the target of a spell an opponent controls, choose one —
• Tectonic Giant deals 3 damage to each opponent.
• Exile the top two cards of your library. Choose one of them. Until the end of your next turn, you may play that card.

Blasphemous Act

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

Valakut Exploration

Landfall — Whenever a land you control enters, exile the top card of your library. You may play that card for as long as it remains exiled.
At the beginning of your end step, if there are cards exiled with Valakut Exploration, put them into their owner's graveyard, then Valakut Exploration deals that much damage to each opponent.

Flame Rift

Flame Rift deals 4 damage to each player.

Brash Taunter

Indestructible
Whenever Brash Taunter is dealt damage, it deals that much damage to target opponent.
{2}{R}, {T}: Brash Taunter fights another target creature.

Earthquake

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

Mindcrank

Whenever an opponent loses life, that player mills that many cards. (Damage causes loss of life.)

Cindervines

Whenever an opponent casts a noncreature spell, Cindervines deals 1 damage to that player.
{1}, Sacrifice Cindervines: Destroy target artifact or enchantment. Cindervines deals 2 damage to that permanent's controller.

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.

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.

Sol Ring

Quakebringer

Your opponents can't gain life.
At the beginning of your upkeep, Quakebringer deals 2 damage to each opponent. This ability triggers only if Quakebringer is on the battlefield or if Quakebringer is in your graveyard and you control a Giant.
Foretell {2}{R}{R}

Chandra's Incinerator

This spell costs {X} less to cast, where X is the total amount of noncombat damage dealt to your opponents this turn.
Trample
Whenever a source you control deals noncombat damage to an opponent, Chandra's Incinerator deals that much damage to target creature or planeswalker that player controls.

Kodama's Reach

Klothys, God of Destiny

Indestructible
As long as your devotion to red and green is less than seven, Klothys isn't a creature.
At the beginning of your first main phase, exile target card from a graveyard. If it was a land card, add {R} or {G}. Otherwise, you gain 2 life and Klothys deals 2 damage to each opponent.

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.

Fiery Confluence

Choose three. You may choose the same mode more than once.
• Fiery Confluence deals 1 damage to each creature.
• Fiery Confluence deals 2 damage to each opponent.
• Destroy target artifact.

Burning Earth

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

Fyndhorn Elves

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Angrath's Marauders

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

Atarka's Command

Choose two —
• Your opponents can't gain life this turn.
• Atarka's Command deals 3 damage to each opponent.
• You may put a land card from your hand onto the battlefield.
• Creatures you control get +1/+1 and gain reach until end of turn.

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.

Elvish Mystic

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Primal Order

At the beginning of each player's upkeep, Primal Order deals damage to that player equal to the number of nonbasic lands they control.

Price of Progress

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

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.)

Chandra, Torch of Defiance

+1: Exile the top card of your library. You may cast that card. If you don't, Chandra, Torch of Defiance deals 2 damage to each opponent.
+1: Add {R}{R}.
−3: Chandra, Torch of Defiance deals 4 damage to target creature.
−7: You get an emblem with "Whenever you cast a spell, this emblem deals 5 damage to any target."

Zhur-Taa Druid

{T}: Add {G}.
Whenever you tap Zhur-Taa Druid for mana, it deals 1 damage to each opponent.

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.