Runaway Steam-Kin

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

Bonus Round

Until end of turn, whenever a player casts an instant or sorcery spell, that player copies it and may choose new targets for the copy.

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. ({R/P} can be paid with either {R} or 2 life.)

Toralf's Hammer

Equipped creature has "{1}{R}, {T}, Unattach Toralf's Hammer: It deals 3 damage to any target. Return Toralf's Hammer to its owner's hand."
Equipped creature gets +3/+0 as long as it's legendary.
Equip {1}{R}

Toralf, God of Fury

Trample
Whenever a creature or planeswalker an opponent controls is dealt excess noncombat damage, Toralf deals damage equal to the excess to any target other than that permanent.

Toralf, God of Fury // Toralf's Hammer

Nahiri's Warcrafting

Nahiri's Warcrafting deals 5 damage to target creature, planeswalker, or battle. Look at the top X cards of your library, where X is the excess damage dealt this way. You may exile one of those cards. Put the rest on the bottom of your library in a random order. You may play the exiled card this turn.

Stonesplitter Bolt

Bargain (You may sacrifice an artifact, enchantment, or token as you cast this spell.)
Stonesplitter Bolt deals X damage to target creature or planeswalker. If this spell was bargained, it deals twice X damage to that permanent instead.

Mirrorwing Dragon

Flying
Whenever a player casts an instant or sorcery spell that targets only this creature, that player copies that spell for each other creature they control that the spell could target. Each copy targets a different one of those creatures.

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.

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.

Mountain

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

Arcane Bombardment

Whenever you cast your first instant or sorcery spell each turn, exile an instant or sorcery card at random from your graveyard. Then copy each card exiled with this enchantment. You may cast any number of the copies without paying their mana costs.

Spiteful Banditry

When this enchantment enters, 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.

Storm King's Thunder

When you next cast an instant or sorcery spell this turn, copy that spell X times. You may choose new targets for the copies.

Seismic Strike

Seismic Strike deals damage to target creature equal to the number of Mountains you control.

Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

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.

Ruby Medallion

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

Big Score

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 token: Add one mana of any color.")

Finale of Promise

You may cast up to one target instant card and/or up to one target sorcery card from your graveyard each with mana value X or less without paying their mana costs. If a spell cast this way would be put into your graveyard, exile it instead. If X is 10 or more, copy each of those spells twice. You may choose new targets for the copies.

Fall of Cair Andros

Whenever a creature an opponent controls is dealt excess noncombat damage, amass Orcs X, where X is that excess damage. (Put X +1/+1 counters on an Army you control. It's also an Orc. If you don't control an Army, create a 0/0 black Orc Army creature token first.)
{7}{R}: This enchantment deals 7 damage to target creature.

Crater's Claws

Crater's Claws deals X damage to any target.
Ferocious — Crater's Claws deals X plus 2 damage instead if you control a creature with power 4 or greater.

Oliphaunt

Trample
Whenever this creature attacks, another target creature you control gets +2/+0 and gains trample until end of turn.
Mountaincycling {1} ({1}, Discard this card: Search your library for a Mountain card, reveal it, put it into your hand, then shuffle.)

Skred

Skred deals damage to target creature equal to the number of snow permanents you control.

Lithoform Engine

{2}, {T}: Copy target activated or triggered ability you control. You may choose new targets for the copy.
{3}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.
{4}, {T}: Copy target permanent spell you control. (The copy becomes a token.)

Primal Wellspring

(Transforms from Primal Amulet.)
{T}: Add one mana of any color. When that mana is spent to cast an instant or sorcery spell, copy that spell and you may choose new targets for the copy.

Primal Amulet

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, put a charge counter on this artifact. Then if there are four or more charge counters on it, you may remove those counters and transform it.

Primal Amulet // Primal Wellspring

Chandra, Torch of Defiance

+1: Exile the top card of your library. You may cast that card. If you don't, Chandra deals 2 damage to each opponent.
+1: Add {R}{R}.
−3: Chandra 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."

Valakut Stoneforge

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

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 this enchantment, put them into their owner's graveyard, then this enchantment deals that much damage to each opponent.

Sol Ring

Seize the Spoils

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

Tormenting Voice

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

Imodane, the Pyrohammer

Whenever an instant or sorcery spell you control that targets only a single creature deals damage to that creature, Imodane deals that much damage to each opponent.

Banefire

Banefire deals X damage to any target.
If X is 5 or more, this spell can't be countered and the damage can't be prevented.

Stuffy Doll

Indestructible
As this creature enters, choose a player.
Whenever this creature is dealt damage, it deals that much damage to the chosen player.
{T}: This creature deals 1 damage to itself.

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.

Purphoros's Intervention

Choose one —
• Create an X/1 red Elemental creature token with trample and haste. Sacrifice it at the beginning of the next end step.
• Purphoros's Intervention deals twice X damage to target creature or planeswalker.

Grapeshot

Grapeshot deals 1 damage to any target.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Shivan Meteor

Shivan Meteor deals 13 damage to target creature.
Suspend 2—{1}{R}{R} (Rather than cast this card from your hand, you may pay {1}{R}{R} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)

Strike It Rich

Create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Experimental Frenzy

You may look at the top card of your library any time.
You may play lands and cast spells from the top of your library.
You can't play lands or cast spells from your hand.
{3}{R}: Destroy this enchantment.

Chandra, Hope's Beacon

Whenever you cast an instant or sorcery spell, copy it. You may choose new targets for the copy. This ability triggers only once each turn.
+2: Add two mana in any combination of colors.
+1: Exile the top five cards of your library. Until the end of your next turn, you may cast an instant or sorcery spell from among those exiled cards.
−X: Chandra deals X damage to each of up to two targets.

Irencrag Feat

Add seven {R}. You can cast only one more spell this turn.

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.

Cathartic Reunion

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

Storm-Kiln Artist

This creature gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Chain of Plasma

Chain of Plasma deals 3 damage to any target. Then that player or that permanent's controller may discard a card. If the player does, they may copy this spell and may choose a new target for that copy.

Commune with Lava

Exile the top X cards of your library. Until the end of your next turn, you may play those cards.

Weight of Spires

Weight of Spires deals damage to target creature equal to the number of nonbasic lands that creature's controller controls.

Zada, Hedron Grinder

Whenever you cast an instant or sorcery spell that targets only Zada, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.

Urza's Rage

Kicker {8}{R} (You may pay an additional {8}{R} as you cast this spell.)
This spell can't be countered.
Urza's Rage deals 3 damage to any target. If this spell was kicked, instead it deals 10 damage to that permanent or player and the damage can't be prevented.

Brash Taunter

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

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, this creature deals that much damage to target creature or planeswalker that player controls.

Tectonic Reformation

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

Fire Servant

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

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Crushing Pain

Crushing Pain deals 6 damage to target creature that was dealt damage this turn.

Spitting Earth

Spitting Earth deals damage to target creature equal to the number of Mountains you control.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Treasonous Ogre

Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Pay 3 life: Add {R}.

Heat Ray

Heat Ray deals X damage to target creature.

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.