Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Warstorm Surge

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

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.

Cursed Mirror

{T}: Add {R}.
As Cursed Mirror enters, you may have it become a copy of any creature on the battlefield until end of turn, except it has haste.

Inspiring Overseer

Flying
When this creature enters, you gain 1 life and draw a card.

Arcane Signet

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

Éomer, Marshal of Rohan

Haste
Whenever one or more other attacking legendary creatures you control die, untap all creatures you control. After this phase, there is an additional combat phase. This ability triggers only once each turn.

Extraplanar Lens

Imprint — When Extraplanar Lens enters, you may exile target land you control.
Whenever a land with the same name as the exiled card is tapped for mana, its controller adds one mana of any type that land produced.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, Warleader's Call deals 1 damage to each opponent.

Plundering Barbarian

When Plundering Barbarian enters, choose one —
• Smash the Chest — Destroy target artifact.
• Pry It Open — Create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Sunrise Sovereign

Other Giant creatures you control get +2/+2 and have trample.

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Myr Battlesphere

When Myr Battlesphere enters, create four 1/1 colorless Myr artifact creature tokens.
Whenever Myr Battlesphere attacks, you may tap X untapped Myr you control. If you do, Myr Battlesphere gets +X/+0 until end of turn and deals X damage to the player or planeswalker it's attacking.

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.)

Scampering Surveyor

When Scampering Surveyor enters, search your library for a basic land card or Cave card, put it onto the battlefield tapped, then shuffle.

Knight of the White Orchid

First strike
When Knight of the White Orchid enters, if an opponent controls more lands than you, you may search your library for a Plains card, put it onto the battlefield, then shuffle.

Kor Cartographer

When Kor Cartographer enters, you may search your library for a Plains card, put it onto the battlefield tapped, then shuffle.

Utvara Hellkite

Flying
Whenever a Dragon you control attacks, create a 6/6 red Dragon creature token with flying.

Duke Ulder Ravengard

At the beginning of combat on your turn, another target creature you control gains haste and myriad until end of turn. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Scourge of Valkas

Flying
Whenever Scourge of Valkas or another Dragon you control enters, it deals X damage to any target, where X is the number of Dragons you control.
{R}: Scourge of Valkas gets +1/+0 until end of turn.

Spirited Companion

When Spirited Companion enters, draw a card.

Zeriam, Golden Wind

Flying
Whenever a Griffin you control deals combat damage to a player, create a 2/2 white Griffin creature token with flying.

Circuit Mender

When Circuit Mender enters, you gain 2 life.
When Circuit Mender leaves the battlefield, draw a card.

Ashnod's Altar

Atsushi, the Blazing Sky

Flying, trample
When Atsushi, the Blazing Sky dies, choose one —
• Exile the top two cards of your library. Until the end of your next turn, you may play those cards.
• Create three Treasure tokens.

Mace of the Valiant

Equipped creature gets +1/+1 for each charge counter on Mace of the Valiant and has vigilance. (Attacking doesn't cause it to tap.)
Whenever a creature you control enters, put a charge counter on Mace of the Valiant.
Equip {3}

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.)

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.

Priest of Ancient Lore

When Priest of Ancient Lore enters, you gain 1 life and draw a card.

Borderland Behemoth

Trample
Borderland Behemoth gets +4/+4 for each other Giant you control.

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

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}

Gilded Lotus

Elturel Survivors

Trample, myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
As long as Elturel Survivors is attacking, it gets +X/+0, where X is the number of lands defending player controls.

Frontline Medic

Battalion — Whenever Frontline Medic and at least two other creatures attack, creatures you control gain indestructible until end of turn.
Sacrifice Frontline Medic: Counter target spell with {X} in its mana cost unless its controller pays {3}.

Echoing Assault

Creature tokens you control have menace.
Whenever you attack a player, choose target nontoken creature that's attacking that player. Create a token that's a copy of that creature, except it's 1/1. The token enters tapped and attacking that player. Sacrifice it at the beginning of the next end step.

Siege-Gang Commander

When Siege-Gang Commander enters, create three 1/1 red Goblin creature tokens.
{1}{R}, Sacrifice a Goblin: Siege-Gang Commander deals 2 damage to any target.

Evangel of Heliod

When Evangel of Heliod enters, create a number of 1/1 white Soldier creature tokens equal to your devotion to white. (Each {W} in the mana costs of permanents you control counts toward your devotion to white.)

Yosei, the Morning Star

Flying
When Yosei, the Morning Star dies, target player skips their next untap step. Tap up to five target permanents that player controls.

Hamletback Goliath

Whenever another creature enters, you may put X +1/+1 counters on Hamletback Goliath, where X is that creature's power.

Angel of Serenity

Flying
When Angel of Serenity enters, you may exile up to three other target creatures from the battlefield and/or creature cards from graveyards.
When Angel of Serenity leaves the battlefield, return the exiled cards to their owners' hands.

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.)

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.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. Talisman of Conviction deals 1 damage to you.

Golden pig

Trumpeting Carnosaur

Trample
When Trumpeting Carnosaur enters, discover 5.
{2}{R}, Discard Trumpeting Carnosaur: It deals 3 damage to target creature or planeswalker.

Taunt from the Rampart

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

Command Tower

Iroas, God of Victory

Indestructible
As long as your devotion to red and white is less than seven, Iroas isn't a creature.
Creatures you control have menace.
Prevent all damage that would be dealt to attacking creatures you control.

Restoration Angel

Flash
Flying
When Restoration Angel enters, you may exile target non-Angel creature you control, then return that card to the battlefield under your control.

Fanatical Devotion

Sacrifice a creature: Regenerate target creature.

Coercive Recruiter

Whenever Coercive Recruiter or another Pirate you control enters, gain control of target creature until end of turn. Untap that creature. Until end of turn, it gains haste and becomes a Pirate in addition to its other types.

Panharmonicon

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

Neyali, Suns' Vanguard

Attacking tokens you control have double strike.
Whenever one or more tokens you control attack a player, exile the top card of your library. During any turn you attacked with a token, you may play that card.

Combustible Gearhulk

First strike
When Combustible Gearhulk enters, target opponent may have you draw three cards. If the player doesn't, you mill three cards, then Combustible Gearhulk deals damage to that player equal to the total mana value of those cards.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

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.

Murasa Pyromancer

Whenever Murasa Pyromancer or another Ally you control enters, you may have Murasa Pyromancer deal damage to target creature equal to the number of Allies you control.

Ao, the Dawn Sky

Flying, vigilance
When Ao, the Dawn Sky dies, choose one —
• Look at the top seven cards of your library. Put any number of nonland permanent cards with total mana value 4 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
• Put two +1/+1 counters on each permanent you control that's a creature or Vehicle.

Nahiri's Resolve

Creatures you control get +1/+0 and have haste.
At the beginning of your end step, exile any number of nontoken artifacts and/or creatures you control. Return those cards to the battlefield under their owner's control at the beginning of your next upkeep.

Patron of the Arts

When Patron of the Arts enters or dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

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.)

Mountain

Devilish Valet

Trample, haste
Alliance — Whenever another creature you control enters, double Devilish Valet's power until end of turn.

Captain of the Watch

Vigilance (Attacking doesn't cause this creature to tap.)
Other Soldier creatures you control get +1/+1 and have vigilance.
When Captain of the Watch enters, create three 1/1 white Soldier creature tokens.

Ox Drover

Vigilance
Ox Drover can't be blocked by Oxen.
Whenever Ox Drover enters or attacks, target opponent creates a 2/4 white Ox creature token and you draw a card.

Herald of the Host

Flying, vigilance
Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Loyal Warhound

Vigilance
When Loyal Warhound enters, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Karmic Guide

Flying, protection from black
Echo {3}{W}{W} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Karmic Guide enters, return target creature card from your graveyard to the battlefield.

Angel of Invention

Flying, vigilance, lifelink
Fabricate 2 (When this creature enters, put two +1/+1 counters on it or create two 1/1 colorless Servo artifact creature tokens.)
Other creatures you control get +1/+1.

Impact Tremors

Whenever a creature you control enters, this enchantment deals 1 damage to each opponent.

Reconnaissance

{0}: Remove target attacking creature you control from combat and untap it. (If you activate during end of combat, the creature will untap after it deals combat damage.)

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.

Sol Ring

Goblin Bombardment

Sacrifice a creature: Goblin Bombardment deals 1 damage to any target.

Plains

Agate Instigator

Offspring {1}{R} (You may pay an additional {1}{R} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Whenever another creature you control enters, this creature deals 1 damage to each opponent.

Battle Angels of Tyr

Flying, myriad
Whenever Battle Angels of Tyr deals combat damage to a player, draw a card if that player has more cards in hand than each other player. Then you create a Treasure token if that player controls more lands than each other player. Then you gain 3 life if that player has more life than each other player.

Wingmate Roc

Flying
Raid — When Wingmate Roc enters, if you attacked this turn, create a 3/4 white Bird creature token with flying.
Whenever Wingmate Roc attacks, you gain 1 life for each attacking creature.

Cavalier of Dawn

Vigilance
When Cavalier of Dawn enters, destroy up to one target nonland permanent. Its controller creates a 3/3 colorless Golem artifact creature token.
When Cavalier of Dawn dies, return target artifact or enchantment card from your graveyard to your hand.

Skyscanner

Flying
When Skyscanner enters, draw a card.

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.)

Tuktuk Scrapper

Whenever Tuktuk Scrapper or another Ally you control enters, you may destroy target artifact. If that artifact is put into a graveyard this way, Tuktuk Scrapper deals damage to that artifact's controller equal to the number of Allies you control.

There and Back Again

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Up to one target creature can't block for as long as you control There and Back Again. The Ring tempts you.
II — Search your library for a Mountain card, put it onto the battlefield, then shuffle.
III — Create Smaug, a legendary 6/6 red Dragon creature token with flying, haste, and "When this creature dies, create fourteen Treasure tokens."

Duergar Hedge-Mage

When Duergar Hedge-Mage enters, if you control two or more Mountains, you may destroy target artifact.
When Duergar Hedge-Mage enters, if you control two or more Plains, you may destroy target enchantment.

Glittering Stockpile

{T}: Add {R}. Put a stash counter on Glittering Stockpile.
{T}, Sacrifice Glittering Stockpile: Add X mana of any one color, where X is the number of stash counters on Glittering Stockpile.

Filigree Familiar

When Filigree Familiar enters, you gain 2 life.
When Filigree Familiar dies, draw a card.

Agrus Kos, Eternal Soldier

Vigilance
Whenever Agrus Kos, Eternal Soldier becomes the target of an ability that targets only it, you may pay {1}{R/W}. If you do, copy that ability for each other creature you control that ability could target. Each copy targets a different one of those creatures. ({R/W} can be paid with either {R} or {W}.)

Sun Titan

Vigilance
Whenever Sun Titan enters or attacks, you may return target permanent card with mana value 3 or less from your graveyard to the battlefield.

Moraug, Fury of Akoum

Each creature you control gets +1/+0 for each time it has attacked this turn.
Landfall — Whenever a land you control enters, if it's your main phase, there's an additional combat phase after this phase. At the beginning of that combat, untap all creatures you control.