Trouble in Pairs

If an opponent would begin an extra turn, that player skips that turn instead.
Whenever an opponent attacks you with two or more creatures, draws their second card each turn, or casts their second spell each turn, you draw a card.

Aurelia, the Warleader

Flying, vigilance, haste
Whenever Aurelia attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.

Selfless Squire

Flash
When this creature enters, prevent all damage that would be dealt to you this turn.
Whenever damage that would be dealt to you is prevented, put that many +1/+1 counters on this creature.

paper proxy

Field Marshal

Other Soldier creatures get +1/+1 and have first strike. (They deal combat damage before creatures without first strike.)

Tori D'Avenant, Fury Rider

Vigilance, trample
Whenever Tori D'Avenant attacks, all other attacking creatures you control get +1/+1 until end of turn. Other red attacking creatures you control gain trample until end of turn. Untap each other white attacking creature you control.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")

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 this creature enters, create three 1/1 white Soldier creature tokens.

Rugged Prairie

{T}: Add {C}.
{R/W}, {T}: Add {R}{R}, {R}{W}, or {W}{W}.

Archetype of Courage

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

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Unclaimed Territory

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Chivalric Alliance

Whenever you attack with two or more creatures, draw a card.
{2}, Discard a card: Create a 2/2 white and blue Knight creature token with vigilance.

Have

Sunhome, Fortress of the Legion

{T}: Add {C}.
{2}{R}{W}, {T}: Target creature gains double strike until end of turn.

Deflecting Palm

The next time a source of your choice would deal damage to you this turn, prevent that damage. If damage is prevented this way, Deflecting Palm deals that much damage to that source's controller.

Valiant Veteran

Other Soldiers you control get +1/+1.
{3}{W}{W}, Exile this card from your graveyard: Put a +1/+1 counter on each Soldier you control.

Baird, Argivian Recruiter

At the beginning of your end step, if you control a creature with power greater than its base power, create a 1/1 white Soldier creature token.

Tajic, Legion's Edge

Haste
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Prevent all noncombat damage that would be dealt to other creatures you control.
{R}{W}: Tajic gains first strike until end of turn.

Molten Echoes

As this enchantment enters, choose a creature type.
Whenever a nontoken creature you control of the chosen type enters, create a token that's a copy of that creature. That token gains haste. Exile it at the beginning of the next end step.

Daru Warchief

Soldier spells you cast cost {1} less to cast.
Soldier creatures you control get +1/+2.

Commander Mustard

Vigilance
Other Soldiers you control have vigilance, trample, and haste.
{2}{R}{W}: Until end of turn, Soldiers you control gain "Whenever this creature attacks, it deals 1 damage to defending player."

Arcane Signet

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

Rising of the Day

Creatures you control have haste.
Legendary creatures you control get +1/+0.

Spectator Seating

This land enters tapped unless you have two or more opponents.
{T}: Add {R} or {W}.

Knight-Captain of Eos

When this creature enters, create two 1/1 white Soldier creature tokens.
{W}, Sacrifice a Soldier: Prevent all combat damage that would be dealt this turn.

Martial Coup

Create X 1/1 white Soldier creature tokens. If X is 5 or more, destroy all other creatures.

Boros Strike-Captain

Battalion — Whenever this creature and at least two other creatures attack, exile the top card of your library. During any turn you attacked with three or more creatures, you may play that card.

Blade Historian

Attacking creatures you control have double strike.

Haazda Marshal

Whenever this creature and at least two other creatures attack, create a 1/1 white Soldier creature token with lifelink.

Boros Signet

Siege Veteran

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
Whenever another nontoken Soldier you control dies, create a 1/1 colorless Soldier artifact creature token.

Gisela, Blade of Goldnight

Flying, first strike
If a source would deal damage to an opponent or a permanent an opponent controls, that source deals double that damage to that player or permanent instead.
If a source would deal damage to you or a permanent you control, prevent half that damage, rounded up.

Hammer of Purphoros

Creatures you control have haste.
{2}{R}, {T}, Sacrifice a land: Create a 3/3 colorless Golem enchantment artifact creature token.

Preeminent Captain

First strike (This creature deals combat damage before creatures without first strike.)
Whenever this creature attacks, you may put a Soldier creature card from your hand onto the battlefield tapped and attacking.

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

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.)

Firemane Commando

Flying
Whenever you attack with two or more creatures, draw a card.
Whenever another player attacks with two or more creatures, they draw a card if none of those creatures attacked you.

Resurgence

Creatures you control gain first strike and vigilance until end of turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Response

Response deals 5 damage to target attacking or blocking creature.

Response // Resurgence

Launch the Fleet

Strive — This spell costs {1} more to cast for each target beyond the first.
Until end of turn, any number of target creatures each gain "Whenever this creature attacks, create a 1/1 white Soldier creature token that's tapped and attacking."

Legion Loyalist

Haste
Battalion — Whenever this creature and at least two other creatures attack, creatures you control gain first strike and trample until end of turn and can't be blocked by creature tokens this turn.

Plains

Akroan Hoplite

Whenever this creature attacks, it gets +X/+0 until end of turn, where X is the number of attacking creatures you control.

Fireflux Squad

Haste
Whenever this creature attacks, you may exile another target attacking creature you control. If you do, reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield tapped and attacking and the rest on the bottom of your library in a random order.

Master Warcraft

Cast this spell only before attackers are declared.
You choose which creatures attack this turn.
You choose which creatures block this turn and how those creatures block.

Fabled Passage

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Darien, King of Kjeldor

Whenever you're dealt damage, you may create that many 1/1 white Soldier creature tokens.

Prismatic Vista

{T}, Pay 1 life, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield, then shuffle.

Sundown Pass

This land enters tapped unless you control two or more other lands.
{T}: Add {R} or {W}.

Unexpected Windfall

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 token: Add one mana of any color.")

Patchwork Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

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.

Balefire Liege

Other red creatures you control get +1/+1.
Other white creatures you control get +1/+1.
Whenever you cast a red spell, this creature deals 3 damage to target player or planeswalker.
Whenever you cast a white spell, you gain 3 life.

Farewell

Choose one or more —
• Exile all artifacts.
• Exile all creatures.
• Exile all enchantments.
• Exile all graveyards.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Keeper of the Accord

At the beginning of each opponent's end step, if that player controls more creatures than you, create a 1/1 white Soldier creature token.
At the beginning of each opponent's end step, if that player controls more lands than you, you may search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Sun Titan

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

Secluded Courtyard

As this land enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type or activate an ability of a creature source of the chosen type.

Mountain

Sacred Foundry

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

Tormenting Voice

Fervor

Creatures you control have haste. (They can attack and {T} as soon as they come under your control.)

Boros Charm

Choose one —
• Boros Charm deals 4 damage to target player or planeswalker.
• Permanents you control gain indestructible until end of turn.
• Target creature gains double strike until end of turn.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Temple of Triumph

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {R} or {W}.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Inspiring Vantage

This land enters tapped unless you control two or fewer other lands.
{T}: Add {R} or {W}.

Cathar Commando

Flash
{1}, Sacrifice this creature: Destroy target artifact or enchantment.

Paladin Elizabeth Taggerdy

Battalion — Whenever Paladin Elizabeth Taggerdy and at least two other creatures attack, draw a card, then you may put a creature card with mana value X or less from your hand onto the battlefield tapped and attacking, where X is Paladin Elizabeth Taggerdy's power.

Catapult Master

Tap five untapped Soldiers you control: Exile target creature.

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.

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.

Vanquisher's Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
Whenever you cast a creature spell of the chosen type, draw a card.

Mobilization

Soldier creatures have vigilance.
{2}{W}: Create a 1/1 white Soldier creature token.

Daru Encampment

{T}: Add {C}.
{W}, {T}: Target Soldier creature gets +1/+1 until end of turn.

Talisman of Conviction

{T}: Add {C}.
{T}: Add {R} or {W}. This artifact deals 1 damage to you.

Frontline Medic

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

Slayers' Stronghold

{T}: Add {C}.
{R}{W}, {T}: Target creature gets +2/+0 and gains vigilance and haste until end of turn.

Battlefield Forge

{T}: Add {C}.
{T}: Add {R} or {W}. This land deals 1 damage to you.

Command Tower

Clifftop Retreat

This land enters tapped unless you control a Mountain or a Plains.
{T}: Add {R} or {W}.

Blasphemous Act

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

Odric, Master Tactician

First strike (This creature deals combat damage before creatures without first strike.)
Whenever Odric and at least three other creatures attack, you choose which creatures block this combat and how those creatures block.

Agrus Kos, Wojek Veteran

Whenever Agrus Kos attacks, attacking red creatures get +2/+0 and attacking white creatures get +0/+2 until end of turn.