Smoke

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

Ob Nixilis, Unshackled

Flying, trample
Whenever an opponent searches their library, that player sacrifices a creature of their choice and loses 10 life.
Whenever another creature dies, put a +1/+1 counter on Ob Nixilis, Unshackled.

Manabarbs

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

Tuktuk the Explorer

Haste
When Tuktuk the Explorer dies, create Tuktuk the Returned, a legendary 5/5 colorless Goblin Golem artifact creature token.

Rakdos Guildgate

This land enters tapped.
{T}: Add {B} or {R}.

Volcanic Wind

Volcanic Wind deals X damage divided as you choose among any number of target creatures, where X is the number of creatures on the battlefield as you cast this spell.

Lavaborn Muse

At the beginning of each opponent's upkeep, if that player has two or fewer cards in hand, Lavaborn Muse deals 3 damage to that player.

Mana Geyser

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Shimmering Grotto

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Hateflayer

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{2}{R}, {Q}: Hateflayer deals damage equal to its power to any target. ({Q} is the untap symbol.)

Black Vise

As Black Vise enters, choose an opponent.
At the beginning of the chosen player's upkeep, Black Vise deals X damage to that player, where X is the number of cards in their hand minus 4.

Fling

As an additional cost to cast this spell, sacrifice a creature.
Fling deals damage equal to the sacrificed creature's power to any target.

Breaking Point

Any player may have Breaking Point deal 6 damage to them. If no one does, destroy all creatures. Creatures destroyed this way can't be regenerated.

Ball Lightning

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Haste (This creature can attack and {T} as soon as it comes under your control.)
At the beginning of the end step, sacrifice this creature.

Prophetic Flamespeaker

Double strike, trample
Whenever Prophetic Flamespeaker deals combat damage to a player, exile the top card of your library. You may play it this turn.

Power of Fire

Enchant creature
Enchanted creature has "{T}: This creature deals 1 damage to any target."

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Lukka, Coppercoat Outcast

+1: Exile the top three cards of your library. Creature cards exiled this way gain "You may cast this card from exile as long as you control a Lukka planeswalker."
−2: Exile target creature you control, then reveal cards from the top of your library until you reveal a creature card with higher mana value. Put that card onto the battlefield and the rest on the bottom of your library in a random order.
−7: Each creature you control deals damage equal to its power to each opponent.

Nevinyrral's Disk

Nevinyrral's Disk enters tapped.
{1}, {T}: Destroy all artifacts, creatures, and enchantments.

Shatterstorm

Destroy all artifacts. They can't be regenerated.

Ruination

Claws of Valakut

Enchant creature
Enchanted creature gets +1/+0 for each Mountain you control and has first strike.

Sarkhan, the Dragonspeaker

+1: Until end of turn, Sarkhan, the Dragonspeaker becomes a legendary 4/4 red Dragon creature with flying, indestructible, and haste. (He doesn't lose loyalty while he's not a planeswalker.)
−3: Sarkhan, the Dragonspeaker deals 4 damage to target creature.
−6: You get an emblem with "At the beginning of your draw step, draw two additional cards" and "At the beginning of your end step, discard your hand."

Hordeling Outburst

Create three 1/1 red Goblin creature tokens.

Swamp

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.

Battle Strain

Whenever a creature blocks, Battle Strain deals 1 damage to that creature's controller.

Sulfur Vent

Sulfur Vent enters tapped.
{T}: Add {B}.
{T}, Sacrifice Sulfur Vent: Add {U}{R}.

Pyroclasm

Pyroclasm deals 2 damage to each creature.

Screaming Fury

Target creature gets +5/+0 and gains haste until end of turn.

Lightning Blast

Lightning Blast deals 4 damage to any target.

Bloodfell Caves

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {R}.

Tribal Flames

Domain — Tribal Flames deals X damage to any target, where X is the number of basic land types among lands you control.

Dwarven Scorcher

Sacrifice Dwarven Scorcher: Dwarven Scorcher deals 1 damage to target creature unless that creature's controller has Dwarven Scorcher deal 2 damage to them.

Ignite Memories

Target player reveals a card at random from their hand. Ignite Memories deals damage to that player equal to that card's mana value.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Blazing Salvo

Blazing Salvo deals 3 damage to target creature unless that creature's controller has Blazing Salvo deal 5 damage to them.

Aggressive Mining

You can't play lands.
Sacrifice a land: Draw two cards. Activate only once each turn.

Disintegrate

Disintegrate deals X damage to any target. If it's a creature, it can't be regenerated this turn, and if it would die this turn, exile it instead.

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.

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.

Mountain

Master of Cruelties

First strike, deathtouch
Master of Cruelties can only attack alone.
Whenever Master of Cruelties attacks a player and isn't blocked, that player's life total becomes 1. Master of Cruelties assigns no combat damage this combat.

Fall of the Hammer

Target creature you control deals damage equal to its power to another target creature.

Shiv's Embrace

Enchant creature
Enchanted creature gets +2/+2 and has flying.
{R}: Enchanted creature gets +1/+0 until end of turn.

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Downhill Charge

You may sacrifice a Mountain rather than pay this spell's mana cost.
Target creature gets +X/+0 until end of turn, where X is the number of Mountains you control.

Incendiary

Enchant creature
At the beginning of your upkeep, you may put a fuse counter on Incendiary.
When enchanted creature dies, Incendiary deals X damage to any target, where X is the number of fuse counters on Incendiary.

Flame Rift

Flame Rift deals 4 damage to each player.

Disaster Radius

As an additional cost to cast this spell, reveal a creature card from your hand.
Disaster Radius deals X damage to each creature your opponents control, where X is the revealed card's mana value.

Flashfires

Kamahl, Pit Fighter

Haste (This creature can attack and {T} as soon as it comes under your control.)
{T}: Kamahl, Pit Fighter deals 3 damage to any target.

Reckless Charge

Target creature gets +3/+0 and gains haste until end of turn.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Mogis, God of Slaughter

Indestructible
As long as your devotion to black and red is less than seven, Mogis isn't a creature.
At the beginning of each opponent's upkeep, Mogis deals 2 damage to that player unless they sacrifice a creature of their choice.

Runaway Steam-Kin

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

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.)

Haze of Rage

Buyback {2} (You may pay an additional {2} as you cast this spell. If you do, put this card into your hand as it resolves.)
Creatures you control get +1/+0 until end of turn.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Recoup

Target sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost. (Mana cost includes color.)
Flashback {3}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Lavaclaw Reaches

Lavaclaw Reaches enters tapped.
{T}: Add {B} or {R}.
{1}{B}{R}: Until end of turn, Lavaclaw Reaches becomes a 2/2 black and red Elemental creature with "{X}: This creature gets +X/+0 until end of turn." It's still a land.

Burning Anger

Enchant creature
Enchanted creature has "{T}: This creature deals damage equal to its power to any target."

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.

Searing Blood

Searing Blood deals 2 damage to target creature. When that creature dies this turn, Searing Blood deals 3 damage to the creature's controller.

Wild Evocation

At the beginning of each player's upkeep, that player reveals a card at random from their hand. If it's a land card, the player puts it onto the battlefield. Otherwise, the player casts it without paying its mana cost if able.

Mob Justice

Mob Justice deals damage to target player or planeswalker equal to the number of creatures you control.

Inflame

Inflame deals 2 damage to each creature dealt damage this turn.

Spire Barrage

Spire Barrage deals damage to any target equal to the number of Mountains you control.

Havoc Festival

Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up.

Jaya Ballard, Task Mage

{R}, {T}, Discard a card: Destroy target blue permanent.
{1}{R}, {T}, Discard a card: Jaya Ballard, Task Mage deals 3 damage to any target. A creature dealt damage this way can't be regenerated this turn.
{5}{R}{R}, {T}, Discard a card: Jaya Ballard deals 6 damage to each creature and each player.

Blaze

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Scorching Missile

Scorching Missile deals 4 damage to target player or planeswalker.
Flashback {9}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Builder's Bane

Destroy X target artifacts. Builder's Bane deals damage to each player equal to the number of artifacts they controlled that were put into a graveyard this way.

Spitting Earth

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