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.

Burnished Hart

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Bojuka Bog

Bojuka Bog enters tapped.
When Bojuka Bog enters, exile target player's graveyard.
{T}: Add {B}.

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.

Spellshock

Whenever a player casts a spell, Spellshock deals 2 damage to that player.

Scab-Clan Berserker

Haste
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever an opponent casts a noncreature spell, if Scab-Clan Berserker is renowned, Scab-Clan Berserker deals 2 damage to that player.

Earthquake

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

Acidic Soil

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

Pain Magnification

Whenever an opponent is dealt 3 or more damage by a single source, that player discards a card.

Sin Prodder

Menace
At the beginning of your upkeep, reveal the top card of your library. Any opponent may have you put that card into your graveyard. If a player does, Sin Prodder deals damage to that player equal to that card's mana value. Otherwise, put that card into your hand.

Glacial Chasm

Cumulative upkeep—Pay 2 life. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When Glacial Chasm enters, sacrifice a land.
Creatures you control can't attack.
Prevent all damage that would be dealt to you.

Goblin Chainwhirler

First strike
When Goblin Chainwhirler enters, it deals 1 damage to each opponent and each creature and planeswalker they control.

Zo-Zu the Punisher

Whenever a land enters, Zo-Zu the Punisher deals 2 damage to that land's controller.

Spinerock Knoll

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.)
Spinerock Knoll enters tapped.
{T}: Add {R}.
{R}, {T}: You may play the exiled card without paying its mana cost if an opponent was dealt 7 or more damage this turn.

Arcbond

Choose target creature. Whenever that creature is dealt damage this turn, it deals that much damage to each other creature and each player.

Risk Factor

Target opponent may have Risk Factor deal 4 damage to them. If that player doesn't, you draw three cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Ambition's Cost

You draw three cards and you lose 3 life.

Fire Diamond

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

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.

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.

Star Compass

Star Compass enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

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.

Kolaghan's Command

Choose two —
• Return target creature card from your graveyard to your hand.
• Target player discards a card.
• Destroy target artifact.
• Kolaghan's Command deals 2 damage to any target.

Rakdos Carnarium

Rakdos Carnarium enters tapped.
When Rakdos Carnarium enters, return a land you control to its owner's hand.
{T}: Add {B}{R}.

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.

Kaervek the Merciless

Whenever an opponent casts a spell, Kaervek the Merciless deals damage equal to that spell's mana value to any target.

Theater of Horrors

At the beginning of your upkeep, exile the top card of your library.
During your turn, if an opponent lost life this turn, you may play lands and cast spells from among cards exiled with Theater of Horrors.
{3}{R}: Theater of Horrors deals 1 damage to target opponent or planeswalker.

Spear Spewer

Defender
{T}: Spear Spewer deals 1 damage to each player.

Cinder Barrens

Cinder Barrens enters tapped.
{T}: Add {B} or {R}.

Steam Blast

Steam Blast deals 2 damage to each creature and each player.

Stunning Reversal

The next time you would lose the game this turn, instead draw seven cards and your life total becomes 1.
Exile Stunning Reversal.

Price of Progress

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

Swamp

Blood Crypt

({T}: Add {B} or {R}.)
As Blood Crypt enters, you may pay 2 life. If you don't, it enters tapped.

Commander's Sphere

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

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.

Terramorphic Expanse

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

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Lightning-Rig Crew

{T}: Lightning-Rig Crew deals 1 damage to each opponent.
Whenever you cast a Pirate spell, untap Lightning-Rig Crew.

Browbeat

Any player may have Browbeat deal 5 damage to them. If no one does, target player draws three cards.

Ancient Craving

Urborg Volcano

Urborg Volcano enters tapped.
{T}: Add {B} or {R}.

Unlicensed Disintegration

Destroy target creature. If you control an artifact, Unlicensed Disintegration deals 3 damage to that creature's controller.

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

Heartless Hidetsugu

{T}: Heartless Hidetsugu deals damage to each player equal to half that player's life total, rounded down.

Rakdos Guildgate

Rakdos Guildgate enters tapped.
{T}: Add {B} or {R}.

Mind Stone

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

Dockside Extortionist

When Dockside Extortionist enters, create X Treasure tokens, where X is the number of artifacts and enchantments your opponents control. (Treasure tokens are artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Stuffy Doll

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

Night's Whisper

Fault Line

Fault Line deals X damage to each creature without flying and each player.

Everlasting Torment

Players can't gain life.
Damage can't be prevented.
All damage is dealt as though its source had wither. (A source with wither deals damage to creatures in the form of -1/-1 counters.)

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Prodigal Pyromancer

{T}: Prodigal Pyromancer 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.

Manabarbs

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

Rampaging Ferocidon

Menace
Players can't gain life.
Whenever another creature enters, Rampaging Ferocidon deals 1 damage to that creature's controller.

Magmaquake

Magmaquake deals X damage to each creature without flying and each planeswalker.

Chandra, Roaring Flame

+1: Chandra, Roaring Flame deals 2 damage to target player or planeswalker.
−2: Chandra, Roaring Flame deals 2 damage to target creature.
−7: Chandra, Roaring Flame deals 6 damage to each opponent. Each player dealt damage this way gets an emblem with "At the beginning of your upkeep, this emblem deals 3 damage to you."

Chandra, Fire of Kaladesh

Whenever you cast a red spell, untap Chandra, Fire of Kaladesh.
{T}: Chandra, Fire of Kaladesh deals 1 damage to target player or planeswalker. If Chandra has dealt 3 or more damage this turn, exile her, then return her to the battlefield transformed under her owner's control.

Chandra, Fire of Kaladesh // Chandra, Roaring Flame

Dragonskull Summit

Dragonskull Summit enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

Obosh, the Preypiercer

Companion — Your starting deck contains only cards with odd mana values and land cards. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
If a source you control with an odd mana value would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Sol Ring

Tunneling Geopede

Landfall — Whenever a land you control enters, Tunneling Geopede deals 1 damage to each opponent.

Soul-Scar Mage

Prowess
If a source you control would deal noncombat damage to a creature an opponent controls, put that many -1/-1 counters on that creature instead.

Volcanic Fallout

This spell can't be countered.
Volcanic Fallout deals 2 damage to each creature and each player.

Smash to Smithereens

Destroy target artifact. Smash to Smithereens deals 3 damage to that artifact's controller.

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.

Evolving Wilds

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

Bloodfell Caves

Bloodfell Caves enters tapped.
When Bloodfell Caves enters, you gain 1 life.
{T}: Add {B} or {R}.

Breath of Malfegor

Breath of Malfegor deals 5 damage to each opponent.

Lightning Berserker

{R}: Lightning Berserker gets +1/+0 until end of turn.
Dash {R} (You may cast this spell for its dash cost. If you do, it gains haste, and it's returned from the battlefield to its owner's hand at the beginning of the next end step.)

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.")

Blasphemous Act

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