Horizon Boughs

All permanents untap during each player's untap step.
Whenever chaos ensues, you may search your library for up to three basic land cards, put them onto the battlefield tapped, then shuffle.

Refraction Elemental

Ward—Pay 2 life.
Whenever you cast a spell, Refraction Elemental deals 2 damage to each opponent.

Invasion of Karsus

(As a Siege enters, choose an opponent to protect it. You and others can attack it. When it's defeated, exile it, then cast it transformed.)
When Invasion of Karsus enters, it deals 3 damage to each creature and each planeswalker.

Invasion of Karsus // Refraction Elemental

Roiling Terrain

Destroy target land, then Roiling Terrain deals damage to that land's controller equal to the number of land cards in that player's graveyard.

Wrenn's Resolve

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

City on Fire

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Feeding Grounds

Red spells cost {1} less to cast.
Green spells cost {1} less to cast.
Whenever chaos ensues, put X +1/+1 counters on target creature, where X is that creature's mana value.

Cavalier of Flame

{1}{R}: Creatures you control get +1/+0 and gain haste until end of turn.
When Cavalier of Flame enters, discard any number of cards, then draw that many cards.
When Cavalier of Flame dies, it deals X damage to each opponent and each planeswalker they control, where X is the number of land cards in your graveyard.

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.

Price of Progress

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

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.

Burning Earth

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

Jaya's Immolating Inferno

(You may cast a legendary sorcery only if you control a legendary creature or planeswalker.)
Jaya's Immolating Inferno deals X damage to each of up to three targets.

Life of the Party

First strike, trample, haste
Whenever Life of the Party attacks, it gets +X/+0 until end of turn, where X is the number of creatures you control.
When Life of the Party enters, if it's not a token, each opponent creates a token that's a copy of it. The tokens are goaded for the rest of the game. (They attack each combat if able and attack a player other than you if able.)

Mountain

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Wake of Destruction

Destroy target land and all other lands with the same name as that land.

Wildfire

Each player sacrifices four lands of their choice. Wildfire deals 4 damage to each creature.

Mirror March

Whenever a nontoken creature you control enters, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

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.

Magmatic Force

At the beginning of each upkeep, Magmatic Force deals 3 damage to any target.

Sol Ring

Charging Cinderhorn

Haste
At the beginning of each player's end step, if no creatures attacked this turn, put a fury counter on Charging Cinderhorn. Then Charging Cinderhorn deals damage equal to the number of fury counters on it to that player.

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.)

Terra Ravager

Whenever Terra Ravager attacks, it gets +X/+0 until end of turn, where X is the number of lands defending player controls.

Norn's Seedcore

When you planeswalk to Norn's Seedcore, chaos ensues.
Whenever chaos ensues, reveal cards from the top of your planar deck until you reveal a plane card. Planeswalk to it, except don't planeswalk away from any plane. Put the rest of the revealed cards on the bottom of your planar deck in any order.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

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.)

Knollspine Dragon

Flying
When Knollspine Dragon enters, you may discard your hand and draw cards equal to the damage dealt to target opponent this turn.

Pyroblast

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

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.

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.

Fractured Powerstone

{T}: Add {C}.
{T}: Roll the planar die. Activate only as a sorcery.

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.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Ignite the Future

Exile the top three cards of your library. Until the end of your next turn, you may play those cards. If this spell was cast from a graveyard, you may play cards this way without paying their mana costs.
Flashback {7}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Naar Isle

At the beginning of your upkeep, put a flame counter on Naar Isle, then Naar Isle deals damage to you equal to the number of flame counters on it.
Whenever chaos ensues, Naar Isle deals 3 damage to target player or planeswalker.

Reckless Impulse

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Arcane Signet

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

Ichor Elixir

If you would roll one or more planar dice, instead roll that many planar dice plus one and ignore one.
{T}: Add {C}{C}.

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

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.

Paliano

When one or more creatures you control deal combat damage to a player, if there is no monarch, you become the monarch.
Whenever chaos ensues, create a 1/1 black Assassin creature token with deathtouch and haste.

Smoldering Crater

Smoldering Crater enters tapped.
{T}: Add {R}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Spatial Merging

When you encounter Spatial Merging, reveal cards from the top of your planar deck until you reveal two plane cards. Simultaneously planeswalk to both of them. Put all other cards revealed this way on the bottom of your planar deck in any order.

Star of Extinction

Destroy target land. Star of Extinction deals 20 damage to each creature and each planeswalker.

Lavakin Brawler

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

Kilnspire District

When you planeswalk to Kilnspire District and at the beginning of your first main phase, put a charge counter on Kilnspire District, then add {R} for each charge counter on it.
Whenever chaos ensues, you may pay {X}. If you do, Kilnspire District deals X damage to any target.

Seismic Elemental

When Seismic Elemental enters, creatures without flying can't block this turn.

Path of the Pyromancer

Discard all the cards in your hand. Add {R} for each card discarded this way, then draw that many cards plus one.
Will of the Planeswalkers — Starting with you, each player votes for planeswalk or chaos. If planeswalk gets more votes, planeswalk. If chaos gets more votes or the vote is tied, chaos ensues.

Ashling the Pilgrim

{1}{R}: Put a +1/+1 counter on Ashling the Pilgrim. If this is the third time this ability has resolved this turn, remove all +1/+1 counters from Ashling the Pilgrim, and it deals that much damage to each creature and each player.

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Time Distortion

When you encounter Time Distortion, reverse the game's turn order. (For example, if play had proceeded clockwise around the table, it now goes counterclockwise. Then planeswalk away from this phenomenon.)

Chaotic Aether

When you encounter Chaotic Aether, each blank roll of the planar die is a {CHAOS} roll until a player planeswalks away from a plane. (Then planeswalk away from this phenomenon.)

Manabarbs

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

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.

Impending Disaster

At the beginning of your upkeep, if there are seven or more lands on the battlefield, sacrifice Impending Disaster and destroy all lands.

Blasphemous Act

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

Sparkspitter

{R}, {T}, Discard a card: Create a 3/1 red Elemental creature token named Spark Elemental. It has trample, haste, and "At the beginning of the end step, sacrifice Spark Elemental."

Chandra's Embercat

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

Shiv

All creatures have "{R}: This creature gets +1/+0 until end of turn."
Whenever chaos ensues, create a 5/5 red Dragon creature token with flying.

Nyx Lotus

Nyx Lotus enters tapped.
{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.)

Furnace Layer

When you planeswalk to Furnace Layer and at the beginning of your upkeep, select target player at random. That player discards a card. If that player discards a land card this way, they lose 3 life.
Whenever chaos ensues, you may destroy target nonland permanent.

Kediss, Emberclaw Familiar

Whenever a commander you control deals combat damage to an opponent, it deals that much damage to each other opponent.
Partner (You can have two commanders if both have partner.)

Battle Hymn

Leyline of Punishment

If Leyline of Punishment is in your opening hand, you may begin the game with it on the battlefield.
Players can't gain life.
Damage can't be prevented.

Leyline Tyrant

Flying
You don't lose unspent red mana as steps and phases end.
When Leyline Tyrant dies, you may pay any amount of {R}. When you do, it deals that much damage to any target.

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.

The Caldaia

Creature spells you cast from your hand have blitz {3}. (If you cast a spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)
Whenever chaos ensues, return target creature card from your graveyard to your hand.

Mana Geyser

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

Mount Keralia

At the beginning of your end step, put a pressure counter on Mount Keralia.
When you planeswalk away from Mount Keralia, it deals damage equal to the number of pressure counters on it to each creature and each planeswalker.
Whenever chaos ensues, prevent all damage that planes named Mount Keralia would deal this game to permanents you control.

Commune with Lava

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

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.

Smokebraider

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

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.

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}.

Obsidian Fireheart

{1}{R}{R}: Put a blaze counter on target land without a blaze counter on it. For as long as that land has a blaze counter on it, it has "At the beginning of your upkeep, this land deals 1 damage to you." (The land continues to burn after Obsidian Fireheart has left the battlefield.)

Sokenzan

All creatures get +1/+1 and have haste.
Whenever chaos ensues, untap all creatures that attacked this turn. If it's a main phase, there is an additional combat phase after this phase, followed by an additional main phase.

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}.

Worn Powerstone

Worn Powerstone enters tapped.
{T}: Add {C}{C}.

Cleansing Wildfire

Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.
Draw a card.

Volcanic Offering

Destroy target nonbasic land you don't control and target nonbasic land of an opponent's choice you don't control.
Volcanic Offering deals 7 damage to target creature you don't control and 7 damage to target creature of an opponent's choice you don't control.