Grateful Apparition

Flying
Whenever this creature deals combat damage to a player or planeswalker, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.

Fuel for the Cause

Counter target spell, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Serum Snare

Return target nonland permanent to its owner's hand. If that permanent had mana value 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Volt Charge

Volt Charge deals 3 damage to any target. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Whirlwind of Thought

Whenever you cast a noncreature spell, draw a card.

Protect the Negotiators

Kicker {W} (You may pay an additional {W} as you cast this spell.)
If this spell was kicked, create a 1/1 white Soldier creature token.
Counter target spell unless its controller pays {1} for each creature you control.

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Steam Vents

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

Eagle Vision

Freerunning {1}{U} (You may cast this spell for its freerunning cost if you dealt combat damage to a player this turn with an Assassin or commander.)
Draw three cards.

Skystrike Officer

Flying
Whenever this creature attacks, create a 1/1 colorless Soldier artifact creature token.
Tap three untapped Soldiers you control: Draw a card.

Spectator Seating

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

Elspeth, Knight-Errant

+1: Create a 1/1 white Soldier creature token.
+1: Target creature gets +3/+3 and gains flying until end of turn.
−8: You get an emblem with "Artifacts, creatures, enchantments, and lands you control have indestructible."

Tekuthal, Inquiry Dominus

Flying
If you would proliferate, proliferate twice instead.
{1}{U/P}{U/P}, Remove three counters from among other artifacts, creatures, and planeswalkers you control: Put an indestructible counter on Tekuthal. ({U/P} can be paid with either {U} or 2 life.)

Azorius Signet

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Mesmerizing Dose

Enchant creature
When this Aura enters, tap enchanted creature, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Enchanted creature doesn't untap during its controller's untap step.

Third Path Iconoclast

Whenever you cast a noncreature spell, create a 1/1 colorless Soldier artifact creature token.

Experimental Augury

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Arcane Signet

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

Resolute Reinforcements

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, create a 1/1 white Soldier creature token.

Immard, the Stormcleaver

Whenever Immard, the Stormcleaver enters or attacks, put a charge counter on it or remove one from it. When you remove a counter this way, choose one —
• Immard deals 4 damage to any target.
• Immard gains lifelink and indestructible until end of turn.

Thrummingbird

Flying
Whenever this creature deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Curate

Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Draw a card.

Clifftop Retreat

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

Electric Revelation

As an additional cost to cast this spell, discard a card.
Draw two cards.
Flashback {3}{R} (You may cast this card from your graveyard for its flashback cost and any additional costs. Then exile it.)

Unbounded Potential

Choose one —
• Put a +1/+1 counter on each of up to two target creatures.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Entwine {3}{W} (Choose both if you pay the entwine cost.)

Combat Celebrant

If this creature 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.)

Vivisurgeon's Insight

Draw three cards. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Izzet Signet

Command Tower

Bloodthirster

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

Captain's Call

Create three 1/1 white Soldier creature tokens.

Viral Drake

Flying
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Contentious Plan

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Swans of Bryn Argoll

Flying
If a source would deal damage to this creature, prevent that damage. The source's controller draws cards equal to the damage prevented this way.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

Distorted Curiosity

Corrupted — This spell costs {2} less to cast if an opponent has three or more poison counters.
Draw two cards.

Mystic Monastery

This land enters tapped.
{T}: Add {U}, {R}, or {W}.

Island

Talisman of Progress

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

Sundown Pass

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

Snap

Return target creature to its owner's hand. Untap up to two lands.

Raugrin Triome

({T}: Add {U}, {R}, or {W}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Training Center

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

Plains

Boros Signet

Haunted Cloak

Equipped creature has vigilance, trample, and haste.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

O-Naginata

This Equipment can be attached only to a creature with power 3 or greater.
Equipped creature gets +3/+0 and has trample.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Mountain

Talisman of Creativity

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

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Talisman of Conviction

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

Lightning Greaves

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

Resourceful Defense

Whenever a permanent you control leaves the battlefield, if it had counters on it, put those counters on target permanent you control.
{4}{W}: Move any number of counters from target permanent you control to another target permanent you control.

Steady Progress

Deserted Beach

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

Gitaxian Anatomist

When this creature enters, you may tap it. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Vexilus Praetor

Flash
Vigilance
Aegis of the Emperor — Commanders you control have protection from everything.

Sea of Clouds

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

Stormcarved Coast

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

Goblin Morningstar

Equipped creature gets +1/+0 and has trample.
Equip {1}{R}
When this Equipment enters, roll a d20.
1—9 | Create a 1/1 red Goblin creature token.
10—20 | Create a 1/1 red Goblin creature token, then attach this Equipment to it.

Ancestral Blade

When this Equipment enters, create a 1/1 white Soldier creature token, then attach this Equipment to it.
Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Norn's Choirmaster

Flying, first strike
Whenever a commander you control enters or attacks, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Flare of Faith

Target creature gets +2/+2 until end of turn. If it's a Human, instead it gets +3/+3 and gains indestructible until end of turn.

Sword of the Animist

Equipped creature gets +1/+1.
Whenever equipped creature attacks, you may search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Equip {2}

The Ozolith

Whenever a creature you control leaves the battlefield, if it had counters on it, put those counters on The Ozolith.
At the beginning of combat on your turn, if The Ozolith has counters on it, you may move all counters from The Ozolith onto target creature.

Reject Imperfection

Counter target spell. If that spell's mana value was 3 or less, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Lulu, Stern Guardian

Whenever an opponent attacks you, choose target creature attacking you. Put a stun counter on that creature.
{3}{U}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.)

Sanctum of Eternity

{T}: Add {C}.
{2}, {T}: Return target commander you own from the battlefield to your hand. Activate only during your turn.

Contagion Engine

When this artifact enters, put a -1/-1 counter on each creature target player controls.
{4}, {T}: Proliferate twice. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Mass Production

Create four 1/1 colorless Soldier artifact creature tokens.

Sulfur Falls

This land enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Guildpact Informant

Cascade Bluffs

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

Hallowed Fountain

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

Inexorable Tide

Whenever you cast a spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Shell Shield

Kicker {1} (You may pay an additional {1} as you cast this spell.)
Target creature you control gets +0/+3 until end of turn. If this spell was kicked, that creature also gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Sacred Foundry

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

Glistening Sphere

This artifact enters tapped.
When this artifact enters, proliferate.
{T}: Add one mana of any color.
Corrupted — {T}: Add three mana of any one color. Activate only if an opponent has three or more poison counters.

Sword of Truth and Justice

Equipped creature gets +2/+2 and has protection from white and from blue.
Whenever equipped creature deals combat damage to a player, put a +1/+1 counter on a creature you control, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Equip {2}

Rugged Prairie

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

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.

Staff of Compleation

{T}, Pay 1 life: Destroy target permanent you own.
{T}, Pay 2 life: Add one mana of any color.
{T}, Pay 3 life: Proliferate.
{T}, Pay 4 life: Draw a card.
{5}: Untap this artifact.