Blood Moon

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.'"

Phyrexian Altar

Sacrifice a creature: Add one mana of any color.

Malignus

Malignus's power and toughness are each equal to half the highest life total among your opponents, rounded up.
Damage that would be dealt by Malignus can't be prevented.

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.)

Burnished Hart

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

Fire Diamond

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

Caterwauling Boggart

Goblins you control and Elementals you control have menace. (They can't be blocked except by two or more creatures.)

Scampering Scorcher

When Scampering Scorcher enters, create two 1/1 red Elemental creature tokens. Elementals you control gain haste until end of turn. (They can attack and {T} this turn.)

Nykthos, Shrine to Nyx

{T}: Add {C}.
{2}, {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.)

Arcane Signet

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

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.

Smokebraider

{T}: Add two mana in any combination of colors. Spend this mana only to cast Elemental spells or activate abilities of Elementals.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

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.

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

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.

Lavakin Brawler

Whenever Lavakin Brawler attacks, it gets +1/+0 until end of turn for each Elemental you control.

Flamekin Village

As Flamekin Village enters, you may reveal an Elemental card from your hand. If you don't, Flamekin Village enters tapped.
{T}: Add {R}.
{R}, {T}: Target creature gains haste until end of turn.

Red Elemental Blast

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

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.")

Mountain

Rite of the Raging Storm

Creatures named Lightning Rager can't attack you or planeswalkers you control.
At the beginning of each player's upkeep, that player creates a 5/1 red Elemental creature token named Lightning Rager. It has trample, haste, and "At the beginning of the end step, sacrifice this creature."

Tilonalli's Summoner

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
Whenever Tilonalli's Summoner attacks, you may pay {X}{R}. If you do, create X 1/1 red Elemental creature tokens that are tapped and attacking. At the beginning of the next end step, exile those tokens unless you have the city's blessing.

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.

Vicious Shadows

Whenever a creature dies, you may have Vicious Shadows deal damage to target player equal to the number of cards in that player's hand.

Mana Echoes

Whenever a creature enters, you may add an amount of {C} equal to the number of creatures you control that share a creature type with it.

Ruby Medallion

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

Chandra's Embercat

{T}: Add {R}. Spend this mana only to cast an Elemental spell or a Chandra planeswalker spell.

Skullclamp

Equipped creature gets +1/-1.
Whenever equipped creature dies, draw two cards.
Equip {1}

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.

Incandescent Soulstoke

Other Elemental creatures you control get +1/+1.
{1}{R}, {T}: You may put an Elemental creature card from your hand onto the battlefield. That creature gains haste until end of turn. Sacrifice it at the beginning of the next end step.

Insurrection

Untap all creatures and gain control of them until end of turn. They gain haste until end of turn.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

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}.

Commander's Sphere

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

Vanquisher's Banner

As Vanquisher's Banner enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Nova Chaser

Trample
Champion an Elemental (When this enters, sacrifice it unless you exile another Elemental you control. When this leaves the battlefield, that card returns to the battlefield.)

Sol Ring

Chandra, Flamecaller

+1: Create two 3/1 red Elemental creature tokens with haste. Exile them at the beginning of the next end step.
0: Discard all the cards in your hand, then draw that many cards plus one.
−X: Chandra, Flamecaller deals X damage to each creature.

Impact Tremors

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

Rakka Mar

Haste
{R}, {T}: Create a 3/1 red Elemental creature token with haste.

Chaos Moon

At the beginning of each upkeep, count the number of permanents. If the number is odd, until end of turn, red creatures get +1/+1 and whenever a player taps a Mountain for mana, that player adds an additional {R}. If the number is even, until end of turn, red creatures get -1/-1 and if a player taps a Mountain for mana, that Mountain produces colorless mana instead of any other type.

Paragon of Fierce Defiance

Other red creatures you control get +1/+1.
{R}, {T}: Another target red creature you control gains haste until end of turn. (It can attack and {T} this turn.)

Tormenting Voice

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

Molten Birth

Create two 1/1 red Elemental creature tokens, then flip a coin. If you win the flip, return Molten Birth to its owner's hand.

Caged Sun

As Caged Sun enters, choose a color.
Creatures you control of the chosen color get +1/+1.
Whenever a land's ability causes you to add one or more mana of the chosen color, add one additional mana of that color.

Blasphemous Act

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

Stalking Vengeance

Haste
Whenever another creature you control dies, it deals damage equal to its power to target player or planeswalker.

Flamekin Harbinger

When Flamekin Harbinger enters, you may search your library for an Elemental card, reveal it, then shuffle and put that card on top.

Mind Stone

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

Magus of the Wheel

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

Flameshadow Conjuring

Whenever a nontoken creature you control enters, you may pay {R}. If you do, create a token that's a copy of that creature. That token gains haste. Exile it at the beginning of the next end step.

Rage Thrower

Whenever another creature dies, Rage Thrower deals 2 damage to target player or planeswalker.

Heart of Ramos

{T}: Add {R}.
Sacrifice Heart of Ramos: Add {R}.

Pyroblast

Choose one —
• Counter target spell if it's blue.
• Destroy target permanent if it's blue.

Ashnod's Altar

Chandra, Novice Pyromancer

+1: Elementals you control get +2/+0 until end of turn.
−1: Add {R}{R}.
−2: Chandra, Novice Pyromancer deals 2 damage to any target.

Thrill of Possibility

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.

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.

Feldon of the Third Path

{2}{R}, {T}: Create a token that's a copy of target creature card in your graveyard, except it's an artifact in addition to its other types. It gains haste. Sacrifice it at the beginning of the next end step.

Primal Beyond

As Primal Beyond enters, you may reveal an Elemental card from your hand. If you don't, Primal Beyond enters tapped.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast an Elemental spell or activate an ability of an Elemental.

Thornbite Staff

Equipped creature has "{2}, {T}: This creature deals 1 damage to any target" and "Whenever a creature dies, untap this creature."
Whenever a Shaman creature enters, you may attach Thornbite Staff to it.
Equip {4}

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Hazoret's Monument

Red creature spells you cast cost {1} less to cast.
Whenever you cast a creature spell, you may discard a card. If you do, draw a card.

Brighthearth Banneret

Elemental spells and Warrior spells you cast cost {1} less to cast.
Reinforce 1—{1}{R} ({1}{R}, Discard this card: Put a +1/+1 counter on target creature.)

Illusionist's Bracers

Whenever an ability of equipped creature is activated, if it isn't a mana ability, copy that ability. You may choose new targets for the copy.
Equip {3}

Soulbright Flamekin

{2}: Target creature gains trample until end of turn. If this is the third time this ability has resolved this turn, you may add {R}{R}{R}{R}{R}{R}{R}{R}.

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.

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.

Anger

Haste
As long as Anger is in your graveyard and you control a Mountain, creatures you control have haste.