Forgotten Ancient

Whenever a player casts a spell, you may put a +1/+1 counter on Forgotten Ancient.
At the beginning of your upkeep, you may move any number of +1/+1 counters from Forgotten Ancient onto other creatures.

Thassa, God of the Sea

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)
At the beginning of your upkeep, scry 1.
{1}{U}: Target creature you control can't be blocked this turn.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Lae'zel, Vlaakith's Champion

If you would put one or more counters on a creature or planeswalker you control or on yourself, put that many plus one of each of those kinds of counters on that permanent or player instead.
Choose a Background (You can have a Background as a second commander.)

Brokers Ascendancy

At the beginning of your end step, put a +1/+1 counter on each creature you control and a loyalty counter on each planeswalker you control.

Seachrome Coast

Seachrome Coast enters tapped unless you control two or fewer other lands.
{T}: Add {W} or {U}.

Trostani, Three Whispers

{1}{G}: Target creature gains deathtouch until end of turn.
{G/W}: Target creature gains vigilance until end of turn.
{2}{W}: Target creature gains double strike until end of turn.

Damning Verdict

Destroy all creatures with no counters on them.

Unexplained Absence

For each player, exile up to one target nonland permanent that player controls. For each permanent exiled this way, its controller cloaks the top card of their library. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Seaside Citadel

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

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.)

Evolution Witness

{1}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Whenever one or more +1/+1 counters are put on Evolution Witness, return target permanent card from your graveyard to your hand.

Grateful Apparition

Flying
Whenever Grateful Apparition 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.)

Island

Fractured Identity

Exile target nonland permanent. Each player other than its controller creates a token that's a copy of it.

Temple of Plenty

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 {G} or {W}.

Decanter of Endless Water

You have no maximum hand size.
{T}: Add one mana of any color.

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Falco Spara, Pactweaver

Flying, trample
Falco Spara, Pactweaver enters with a shield counter on it.
You may look at the top card of your library any time.
You may cast spells from the top of your library by removing a counter from a creature you control in addition to paying their other costs.

Vineglimmer Snarl

As Vineglimmer Snarl enters, you may reveal a Forest or Island card from your hand. If you don't, Vineglimmer Snarl enters tapped.
{T}: Add {G} or {U}.

Comeuppance

Prevent all damage that would be dealt to you and planeswalkers you control this turn by sources you don't control. If damage from a creature source is prevented this way, Comeuppance deals that much damage to that creature. If damage from a noncreature source is prevented this way, Comeuppance deals that much damage to the source's controller.

Ezuri, Stalker of Spheres

When Ezuri, Stalker of Spheres enters, you may pay {3}. If you do, proliferate twice.
Whenever you proliferate, draw a card.

Arcane Signet

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

Plains

Arwen, Mortal Queen

Arwen, Mortal Queen enters with an indestructible counter on it.
{1}, Remove an indestructible counter from Arwen: Another target creature gains indestructible until end of turn. Put a +1/+1 counter and a lifelink counter on that creature and a +1/+1 counter and a lifelink counter on Arwen.

Rhoda, Geist Avenger

Partner with Timin, Youthful Geist (When this creature enters, target player may put Timin into their hand from their library, then shuffle.)
Vigilance
Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, put a +1/+1 counter on Rhoda, Geist Avenger.

Metastatic Evangel

Whenever another nontoken creature you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.

Thrummingbird

Flying
Whenever Thrummingbird 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.)

Tidechannel Pathway

Barkchannel Pathway

Barkchannel Pathway // Tidechannel Pathway

Command Tower

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

Park Heights Maverick

Dethrone (Whenever this creature attacks the player with the most life or tied for the most life, put a +1/+1 counter on it.)
Park Heights Maverick can't be blocked by creatures with power 2 or less.
Whenever Park Heights Maverick deals combat damage to a player or dies, proliferate.

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Branching Evolution

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

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.)

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.)

No More Lies

Counter target spell unless its controller pays {3}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Hylda of the Icy Crown

Whenever you tap an untapped creature an opponent controls, you may pay {1}. When you do, choose one —
• Create a 4/4 white and blue Elemental creature token.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Fortified Village

As Fortified Village enters, you may reveal a Forest or Plains card from your hand. If you don't, Fortified Village enters tapped.
{T}: Add {G} or {W}.

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Contagion Engine

When Contagion Engine 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.)

Evolutionary Escalation

At the beginning of your upkeep, put three +1/+1 counters on target creature you control and three +1/+1 counters on target creature an opponent controls.

Repulsive Mutation

Put X +1/+1 counters on target creature you control. Then counter up to one target spell unless its controller pays mana equal to the greatest power among creatures you control.

The Wandering Emperor

Flash
As long as The Wandering Emperor entered this turn, you may activate her loyalty abilities any time you could cast an instant.
+1: Put a +1/+1 counter on up to one target creature. It gains first strike until end of turn.
−1: Create a 2/2 white Samurai creature token with vigilance.
−2: Exile target tapped creature. You gain 2 life.

Tolarian Contempt

When Tolarian Contempt enters, put a rejection counter on each creature your opponents control.
At the beginning of your end step, for each opponent, choose up to one target creature they control with a rejection counter on it. That creature's owner puts it on their choice of the top or bottom of their library.

Kros, Defense Contractor

At the beginning of your upkeep, put a shield counter on target creature an opponent controls.
Whenever you put one or more counters on a creature you don't control, tap that creature and goad it. It gains trample until your next turn. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Temple of Mystery

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 {G} or {U}.

Sol Ring

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Split Up

Choose one —
• Destroy all tapped creatures.
• Destroy all untapped creatures.

Generous Patron

When Generous Patron enters, support 2. (Put a +1/+1 counter on each of up to two other target creatures.)
Whenever you put one or more counters on a creature you don't control, draw a card.

Fell the Mighty

Destroy all creatures with power greater than target creature's power.

Hinterland Harbor

Hinterland Harbor enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Thought Vessel

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

Forest

Fangs of Kalonia

Put a +1/+1 counter on target creature you control, then double the number of +1/+1 counters on each creature that had a +1/+1 counter put on it this way.
Overload {4}{G}{G} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Glen Elendra Archmage

Flying
{U}, Sacrifice Glen Elendra Archmage: Counter target noncreature spell.
Persist (When this creature dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Galadriel, Light of Valinor

Alliance — Whenever another creature you control enters, choose one that hasn't been chosen this turn —
• Add {G}{G}{G}.
• Put a +1/+1 counter on each creature you control.
• Scry 2, then draw a card.

Sungrass Prairie

Mangara, the Diplomat

Lifelink
Whenever an opponent attacks with creatures, if two or more of those creatures are attacking you and/or planeswalkers you control, draw a card.
Whenever an opponent casts their second spell each turn, draw a card.

Canopy Vista

({T}: Add {G} or {W}.)
Canopy Vista enters tapped unless you control two or more basic lands.

Fathom Mage

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever a +1/+1 counter is put on Fathom Mage, you may draw a card.

Tamiyo, Field Researcher

+1: Choose up to two target creatures. Until your next turn, whenever either of those creatures deals combat damage, you draw a card.
−2: Tap up to two target nonland permanents. They don't untap during their controller's next untap step.
−7: Draw three cards. You get an emblem with "You may cast spells from your hand without paying their mana costs."

Deepglow Skate

When Deepglow Skate enters, double the number of each kind of counter on any number of target permanents.

Defiler of Vigor

Trample
As an additional cost to cast green permanent spells, you may pay 2 life. Those spells cost {G} less to cast if you paid life this way. This effect reduces only the amount of green mana you pay.
Whenever you cast a green permanent spell, put a +1/+1 counter on each creature you control.

Wizard Class

(Gain the next level as a sorcery to add its ability.)
You have no maximum hand size.
{2}{U}: Level 2
When this Class becomes level 2, draw two cards.
{4}{U}: Level 3
Whenever you draw a card, put a +1/+1 counter on target creature you control.

Cankerbloom

{1}, Sacrifice Cankerbloom: Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Sheltering Ancient

Trample
Cumulative upkeep—Put a +1/+1 counter on a creature an opponent controls. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Kutzil, Malamet Exemplar

Your opponents can't cast spells during your turn.
Whenever one or more creatures you control each with power greater than its base power deals combat damage to a player, draw a card.

Ledger Shredder

Flying
Whenever a player casts their second spell each turn, Ledger Shredder connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Herald of Secret Streams

Creatures you control with +1/+1 counters on them can't be blocked.

Bountiful Promenade

Bountiful Promenade enters tapped unless you have two or more opponents.
{T}: Add {G} or {W}.

Prairie Stream

({T}: Add {W} or {U}.)
Prairie Stream enters tapped unless you control two or more basic lands.

Exotic Orchard

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

Sea of Clouds

Sea of Clouds enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Flare of Fortitude

You may sacrifice a nontoken white creature rather than pay this spell's mana cost.
Until end of turn, your life total can't change, and permanents you control gain hexproof and indestructible.

Ripples of Potential

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Court of Garenbrig

When Court of Garenbrig enters, you become the monarch.
At the beginning of your upkeep, distribute two +1/+1 counters among up to two target creatures. Then if you're the monarch, double the number of +1/+1 counters on each creature you control.

Razorverge Thicket

Razorverge Thicket enters tapped unless you control two or fewer other lands.
{T}: Add {G} or {W}.

Basking Broodscale

Devoid (This card has no color.)
{1}{G}: Adapt 1. (If this creature has no +1/+1 counters on it, put a +1/+1 counter on it.)
Whenever one or more +1/+1 counters are put on Basking Broodscale, you may create a 0/1 colorless Eldrazi Spawn creature token with "Sacrifice this creature: Add {C}."

Pollywog Prodigy

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever an opponent casts a noncreature spell with mana value less than Pollywog Prodigy's power, draw a card.

Verity Circle

Whenever a creature an opponent controls becomes tapped, if it isn't being declared as an attacker, you may draw a card.
{4}{U}: Tap target creature without flying.