Arcbond

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

Karlach, Fury of Avernus

Whenever you attack, if it's the first combat phase of the turn, untap all attacking creatures. They gain first strike until end of turn. After this phase, there is an additional combat phase.
Choose a Background (You can have a Background as a second commander.)

Mountain

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Grim Monolith

Grim Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{4}: Untap Grim Monolith.

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.

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Ruby Medallion

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

Mirror Gallery

Blood Crypt

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

Berserkers' Onslaught

Attacking creatures you control have double strike.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Damnation

Destroy all creatures. They can't be regenerated.

Warstorm Surge

Whenever a creature you control enters, it deals damage equal to its power to any target.

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Commander's Plate

Equipped creature gets +3/+3 and has protection from each color that's not in your commander's color identity.
Equip commander {3}
Equip {5}

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.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Browbeat

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

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.

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Jeska's Will

Choose one. If you control a commander as you cast this spell, you may choose both instead.
• Add {R} for each card in target opponent's hand.
• Exile the top three cards of your library. You may play them this turn.

Gauntlet of Might

Red creatures get +1/+1.
Whenever a Mountain is tapped for mana, its controller adds an additional {R}.

Nether Void

Whenever a player casts a spell, counter it unless that player pays {3}.

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.)

Exquisite Blood

Whenever an opponent loses life, you gain that much life.

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.

No Mercy

Whenever a creature deals damage to you, destroy it.

Luxury Suite

Luxury Suite enters tapped unless you have two or more opponents.
{T}: Add {B} or {R}.

Call of the Ring

At the beginning of your upkeep, the Ring tempts you.
Whenever you choose a creature as your Ring-bearer, you may pay 2 life. If you do, draw a card.

Brass's Bounty

For each land you control, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

Sanguine Bond

Whenever you gain life, target opponent loses that much life.

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 artifact: Add one mana of any color.")

Urborg, Tomb of Yawgmoth

Each land is a Swamp in addition to its other land types.

Decree of Pain

Destroy all creatures. They can't be regenerated. Draw a card for each creature destroyed this way.
Cycling {3}{B}{B} ({3}{B}{B}, Discard this card: Draw a card.)
When you cycle Decree of Pain, all creatures get -2/-2 until end of turn.

Phyrexian Arena

At the beginning of your upkeep, you draw a card and you lose 1 life.

Revel in Riches

Whenever a creature an opponent controls dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")
At the beginning of your upkeep, if you control ten or more Treasures, you win the game.

Pyramid of the Pantheon

{2}, {T}: Add one mana of any color. Put a brick counter on Pyramid of the Pantheon.
{T}: Add three mana of any one color. Activate only if there are three or more brick counters on Pyramid of the Pantheon.

Gratuitous Violence

If a creature you control would deal damage to a permanent or player, it deals double that damage instead.

Thran Dynamo

Unexpected Windfall

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

The Reaver Cleaver

Equipped creature gets +1/+1 and has trample and "Whenever this creature deals combat damage to a player or planeswalker, create that many Treasure tokens."
Equip {3}

Defense Grid

Each spell costs {3} more to cast except during its controller's turn.

Deadly Rollick

If you control a commander, you may cast this spell without paying its mana cost.
Exile target creature.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

Blasphemous Act

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

Helm of the Host

At the beginning of combat on your turn, create a token that's a copy of equipped creature, except the token isn't legendary. That token gains haste.
Equip {5}

Vampiric Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Chromatic Orrery

You may spend mana as though it were mana of any color.
{T}: Add {C}{C}{C}{C}{C}.
{5}, {T}: Draw a card for each color among permanents you control.

Smoldering Marsh

({T}: Add {B} or {R}.)
Smoldering Marsh enters tapped unless you control two or more basic lands.

Disrupt Decorum

Goad all creatures you don't control. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)

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.

Dragonskull Summit

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

Swamp

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.

Quest for Pure Flame

Whenever a source you control deals damage to an opponent, you may put a quest counter on Quest for Pure Flame.
Remove four quest counters from Quest for Pure Flame and sacrifice it: If any source you control would deal damage to a permanent or player this turn, it deals double that damage to that permanent or player instead.

Black Market Connections

At the beginning of your first main phase, choose one or more —
• Sell Contraband — Create a Treasure token. You lose 1 life.
• Buy Information — Draw a card. You lose 2 life.
• Hire a Mercenary — Create a 3/2 colorless Shapeshifter creature token with changeling. You lose 3 life. (It has every creature type.)

Basalt Monolith

Basalt Monolith doesn't untap during your untap step.
{T}: Add {C}{C}{C}.
{3}: Untap Basalt Monolith.

Mechanized Warfare

If a red or artifact source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 1 instead.

Arcane Signet

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

Blaze

Mirage Mirror

{2}: Mirage Mirror becomes a copy of target artifact, creature, enchantment, or land until end of turn.

Thought Vessel

Command Tower

Sol Ring

Agent of the Iron Throne

Commander creatures you own have "Whenever an artifact or creature you control is put into a graveyard from the battlefield, each opponent loses 1 life."

Fellwar Stone

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

Cabal Stronghold

{T}: Add {C}.
{3}, {T}: Add {B} for each basic Swamp 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.)

Gilded Lotus

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.