Treasonous Ogre

Dethrone (Whenever this creature attacks the player with the most life or tied for most life, put a +1/+1 counter on it.)
Pay 3 life: Add {R}.

Terror of the Peaks

Flying
Spells your opponents cast that target Terror of the Peaks cost an additional 3 life to cast.
Whenever another creature you control enters, Terror of the Peaks deals damage equal to that creature's power to any target.

Shinka, the Bloodsoaked Keep

{T}: Add {R}.
{R}, {T}: Target legendary creature gains first strike until end of turn.

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.

Ulamog, the Ceaseless Hunger

When you cast this spell, exile two target permanents.
Indestructible
Whenever Ulamog, the Ceaseless Hunger attacks, defending player exiles the top twenty cards of their library.

Arcane Signet

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

Generator Servant

{T}, Sacrifice Generator Servant: Add {C}{C}. If that mana is spent on a creature spell, it gains haste until end of turn. (That creature can attack and {T} as soon as it comes under your control.)

Archetype of Aggression

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

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}

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.

Relentless Assault

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Void Winnower

Your opponents can't cast spells with even mana values. (Zero is even.)
Your opponents can't block with creatures with even mana values.

Pyroblast

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

Ruby Medallion

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

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.

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}

Sandstone Oracle

Flying
When Sandstone Oracle enters, choose an opponent. If that player has more cards in hand than you, draw cards equal to the difference.

Savage Beating

Cast this spell only during your turn and only during combat.
Choose one —
• Creatures you control gain double strike until end of turn.
• Untap all creatures you control. After this phase, there is an additional combat phase.
Entwine {1}{R} (Choose both if you pay the entwine cost.)

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.

Rage Reflection

Creatures you control have double strike.

Thundermare

Haste (This creature can attack and {T} as soon as it comes under your control.)
When Thundermare enters, tap all other creatures.

Mana Geyser

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

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Blightsteel Colossus

Trample, infect, indestructible
If Blightsteel Colossus would be put into a graveyard from anywhere, reveal Blightsteel Colossus and shuffle it into its owner's library instead.

Kozilek, Butcher of Truth

When you cast this spell, draw four cards.
Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents of their choice.)
When Kozilek, Butcher of Truth is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

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.

Avatar of Slaughter

All creatures have double strike and attack each combat if able.

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.)

Gratuitous Violence

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

Balefire Dragon

Flying
Whenever Balefire Dragon deals combat damage to a player, it deals that much damage to each creature that player controls.

Temur Battle Rage

Target creature gains double strike until end of turn.
Ferocious — That creature also gains trample until end of turn if you control a creature with power 4 or greater.

Where Ancients Tread

Whenever a creature you control with power 5 or greater enters, you may have Where Ancients Tread deal 5 damage to any target.

Port Razer

Whenever Port Razer deals combat damage to a player, untap each creature you control. After this phase, there is an additional combat phase.
Port Razer can't attack a player it has already attacked this turn.

Godo, Bandit Warlord

When Godo, Bandit Warlord enters, you may search your library for an Equipment card, put it onto the battlefield, then shuffle.
Whenever Godo attacks for the first time each turn, untap it and all Samurai you control. After this phase, there is an additional combat phase.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Arni Metalbrow

Whenever a creature you control attacks or a creature you control enters attacking, you may pay {1}{R}. If you do, you may put a creature card with mana value less than that creature's mana value from your hand onto the battlefield tapped and attacking.

Spawn of Thraxes

Flying
When Spawn of Thraxes enters, it deals damage to any target equal to the number of Mountains you control.

Seething Song

Pathrazer of Ulamog

Annihilator 3 (Whenever this creature attacks, defending player sacrifices three permanents of their choice.)
Pathrazer of Ulamog can't be blocked except by three or more creatures.

Ragavan, Nimble Pilferer

Whenever Ragavan, Nimble Pilferer deals combat damage to a player, create a Treasure token and exile the top card of that player's library. Until end of turn, you may cast that card.
Dash {1}{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.)

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.

Bloodthirster

Flying, trample
Whenever Bloodthirster deals combat damage to a player, untap it. After this phase, there is an additional combat phase.
Bloodthirster can't attack a player it has already attacked this turn.

It That Betrays

Annihilator 2 (Whenever this creature attacks, defending player sacrifices two permanents of their choice.)
Whenever an opponent sacrifices a nontoken permanent, put that card onto the battlefield under your control.

Breaker of Armies

All creatures able to block Breaker of Armies do so.

Red Elemental Blast

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

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.

Dolmen Gate

Prevent all combat damage that would be dealt to attacking creatures you control.

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.)

Ulamog, the Infinite Gyre

When you cast this spell, destroy target permanent.
Indestructible
Annihilator 4 (Whenever this creature attacks, defending player sacrifices four permanents of their choice.)
When Ulamog, the Infinite Gyre is put into a graveyard from anywhere, its owner shuffles their graveyard into their library.

Bolt Bend

This spell costs {3} less to cast if you control a creature with power 4 or greater.
Change the target of target spell or ability with a single target.

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.")

Terror of Mount Velus

Flying
Double strike (This creature deals both first-strike and regular combat damage.)
When this creature enters, creatures you control gain double strike until end of turn.

Demanding Dragon

Flying
When Demanding Dragon enters, it deals 5 damage to target opponent unless that player sacrifices a creature of their choice.

Meteor Golem

When this creature enters, destroy target nonland permanent an opponent controls.

Professional Face-Breaker

Menace
Whenever one or more creatures you control deal combat damage to a player, create a Treasure token.
Sacrifice a Treasure: Exile the top card of your library. You may play that card this turn.

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.

Silverclad Ferocidons

Enrage — Whenever Silverclad Ferocidons is dealt damage, each opponent sacrifices a permanent of their choice.

Combat Celebrant

If Combat Celebrant hasn't been exerted this turn, you may exert it as it attacks. When you do, untap all other creatures you control and after this phase, there is an additional combat phase. (An exerted creature won't untap during your next untap step.)

Ancient Copper Dragon

Flying
Whenever Ancient Copper Dragon deals combat damage to a player, roll a d20. You create a number of Treasure tokens equal to the result.

Ilharg, the Raze-Boar

Trample
Whenever Ilharg, the Raze-Boar attacks, you may put a creature card from your hand onto the battlefield tapped and attacking. Return that creature to your hand at the beginning of the next end step.
When Ilharg, the Raze-Boar dies or is put into exile from the battlefield, you may put it into its owner's library third from the top.

Warstorm Surge

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

Blasphemous Act

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

Kozilek, the Great Distortion

When you cast this spell, if you have fewer than seven cards in hand, draw cards equal to the difference.
Menace
Discard a card with mana value X: Counter target spell with mana value X.

Injury

Aftermath (Cast this spell only from your graveyard. Then exile it.)
Injury deals 2 damage to target creature and 2 damage to target player or planeswalker.

Insult

Damage can't be prevented this turn. If a source you control would deal damage this turn, it deals double that damage instead.

Insult // Injury

Fiery Emancipation

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

Tibalt's Trickery

Counter target spell. Choose 1, 2, or 3 at random. Its controller mills that many cards, then exiles cards from the top of their library until they exile a nonland card with a different name than that spell. They may cast that card without paying its mana cost. Then they put the exiled cards on the bottom of their library in a random order.

Goldspan Dragon

Flying, haste
Whenever Goldspan Dragon attacks or becomes the target of a spell, create a Treasure token.
Treasures you control have "{T}, Sacrifice this artifact: Add two mana of any one color."

Sneak Attack

{R}: You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice the creature at the beginning of the next end step.