Grolnok, the Omnivore

Whenever a Frog you control attacks, mill three cards.
Whenever a permanent card is put into your graveyard from your library, exile it with a croak counter on it.
You may play lands and cast spells from among cards you own in exile with croak counters on them.

Command Tower

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

Yavimaya Coast

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

Hinterland Harbor

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

Rejuvenating Springs

Rejuvenating Springs enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Dreamroot Cascade

Dreamroot Cascade enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Breeding Pool

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

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}.

Hedge Maze

({T}: Add {G} or {U}.)
Hedge Maze enters tapped.
When Hedge Maze enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Exotic Orchard

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

Tidechannel Pathway

Barkchannel Pathway

Barkchannel Pathway // Tidechannel Pathway

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Flooded Grove

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

Waterlogged Grove

{T}, Pay 1 life: Add {G} or {U}.
{1}, {T}, Sacrifice Waterlogged Grove: Draw a card.

Overflowing Basin

City of Brass

Whenever City of Brass becomes tapped, it deals 1 damage to you.
{T}: Add one mana of any color.

Mana Confluence

{T}, Pay 1 life: Add one mana of any color.

Botanical Sanctum

Botanical Sanctum enters tapped unless you control two or fewer other lands.
{T}: Add {G} or {U}.

Yavimaya, Cradle of Growth

Each land is a Forest in addition to its other land types.

Boseiju, Who Endures

{T}: Add {G}.
Channel — {1}{G}, Discard Boseiju, Who Endures: Destroy target artifact, enchantment, or nonbasic land an opponent controls. That player may search their library for a land card with a basic land type, put it onto the battlefield, then shuffle. This ability costs {1} less to activate for each legendary creature you control.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Field of the Dead

Field of the Dead enters tapped.
{T}: Add {C}.
Whenever Field of the Dead or another land you control enters, if you control seven or more lands with different names, create a 2/2 black Zombie creature token.

Island

Forest

Alchemist's Refuge

{T}: Add {C}.
{G}{U}, {T}: You may cast spells this turn as though they had flash.

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice Emergence Zone: You may cast spells this turn as though they had flash.

Tropical Island

Plaza of Heroes

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell.
{T}: Add one mana of any color among legendary permanents you control.
{3}, {T}, Exile Plaza of Heroes: Target legendary creature gains hexproof and indestructible until end of turn.

Cavern of Souls

As Cavern of Souls 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, and that spell can't be countered.

Command Beacon

{T}: Add {C}.
{T}, Sacrifice Command Beacon: Put your commander into your hand from the command zone.

Cephalid Coliseum

{T}: Add {U}. Cephalid Coliseum deals 1 damage to you.
Threshold — {U}, {T}, Sacrifice Cephalid Coliseum: Target player draws three cards, then discards three cards. Activate only if seven or more cards are in your graveyard.

Lilypad Village

{T}: Add {C}.
{T}: Add {U}. Spend this mana only to cast a creature spell.
{U}, {T}: Surveil 2. Activate only if a Bird, Frog, Otter, or Rat entered the battlefield under your control this turn.

Seat of the Synod

Tree of Tales

Okina, Temple to the Grandfathers

{T}: Add {G}.
{G}, {T}: Target legendary creature gets +1/+1 until end of turn.

Oakhollow Village

{T}: Add {C}.
{T}: Add {G}. Spend this mana only to cast a creature spell.
{G}, {T}: Put a +1/+1 counter on each Frog, Rabbit, Raccoon, or Squirrel you control that entered the battlefield this turn.

Hermit Druid

{G}, {T}: Reveal cards from the top of your library until you reveal a basic land card. Put that card into your hand and all other cards revealed this way into your graveyard.

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Chronic Flooding

Enchant land
Whenever enchanted land becomes tapped, its controller mills three cards.

Codex Shredder

{T}: Target player mills a card. (They put the top card of their library into their graveyard.)
{5}, {T}, Sacrifice Codex Shredder: Return target card from your graveyard to your hand.

Court of Cunning

When Court of Cunning enters, you become the monarch.
At the beginning of your upkeep, any number of target players each mill two cards. If you're the monarch, each of those players mills ten cards instead. (To mill a card, a player puts the top card of their library into their graveyard.)

Cut Your Losses

Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Target player mills half their library, rounded down.

Dreamborn Muse

At the beginning of each player's upkeep, that player mills X cards, where X is the number of cards in their hand.

Fleet Swallower

Whenever Fleet Swallower attacks, target player mills half their library, rounded up.

Fraying Sanity

Enchant player
At the beginning of each end step, enchanted player mills X cards, where X is the number of cards put into their graveyard from anywhere this turn.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards.

Mesmeric Orb

Whenever a permanent becomes untapped, that permanent's controller mills a card.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

Traumatize

Target player mills half their library, rounded down.

Wand of Vertebrae

{T}: Mill a card.
{2}, {T}, Exile Wand of Vertebrae: Shuffle up to five target cards from your graveyard into your library.

Drowned Secrets

Whenever you cast a blue spell, target player mills two cards.

Ghoulcaller's Bell

Crop Sigil

At the beginning of your upkeep, you may mill a card.
Delirium — {2}{G}, Sacrifice Crop Sigil: Return up to one target creature card and up to one target land card from your graveyard to your hand. Activate only if there are four or more card types among cards in your graveyard.

Rampant Frogantua

Trample
Rampant Frogantua gets +10/+10 for each player who has lost the game.
Whenever Rampant Frogantua deals combat damage to a player, you may mill that many cards. Put any number of land cards from among them onto the battlefield tapped.

Cephalid Illusionist

Whenever Cephalid Illusionist becomes the target of a spell or ability, mill three cards.
{2}{U}, {T}: Prevent all combat damage that would be dealt to and dealt by target creature you control this turn.

Lightning Greaves

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

Frilled Mystic

Flash
When Frilled Mystic enters, you may counter target spell.

Mystic Snake

Flash
When Mystic Snake enters, counter target spell.

Long River Lurker

Ward {1}
Other Frogs you control have ward {1}.
When Long River Lurker enters, target creature you control can't be blocked this turn. Whenever that creature deals combat damage this turn, you may exile it. If you do, return it to the battlefield under its owner's control.

Amphibian Downpour

Flash
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies. Copies become tokens.)
Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1.

Doc Aurlock, Grizzled Genius

Spells you cast from your graveyard or from exile cost {2} less to cast.
Plotting cards from your hand costs {2} less.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Spore Frog

Sacrifice Spore Frog: Prevent all combat damage that would be dealt this turn.

Omnibian

{T}: Target creature becomes a Frog with base power and toughness 3/3 until end of turn.

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Savvy Trader

When Savvy Trader enters, exile target permanent card from your graveyard. You may play that card for as long as it remains exiled.
Spells you cast from anywhere other than your hand cost {1} less to cast.

Poison Dart Frog

Reach
{T}: Add one mana of any color.
{2}: Poison Dart Frog gains deathtouch until end of turn.

Millikin

{T}, Mill a card: Add {C}. (To mill a card, put the top card of your library into your graveyard.)

Llanowar Elves

Exploration

You may play an additional land on each of your turns.

Elvish Mystic

Deranged Assistant

Birds of Paradise

Azusa, Lost but Seeking

You may play two additional lands on each of your turns.

Arcane Signet

Frogify

Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1. (It loses all other card types and creature types.)

Lotus Cobra

Landfall — Whenever a land you control enters, add one mana of any color.

Dryad of the Ilysian Grove

You may play an additional land on each of your turns.
Lands you control are every basic land type in addition to their other types.

Wayward Swordtooth

Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
You may play an additional land on each of your turns.
Wayward Swordtooth can't attack or block unless you have the city's blessing.

Oracle of Mul Daya

You may play an additional land on each of your turns.
Play with the top card of your library revealed.
You may play lands from the top of your library.

Aesi, Tyrant of Gyre Strait

You may play an additional land on each of your turns.
Landfall — Whenever a land you control enters, you may draw a card.

Green Sun's Zenith

Search your library for a green creature card with mana value X or less, put it onto the battlefield, then shuffle. Shuffle Green Sun's Zenith into its owner's library.

Intuition

Search your library for three cards and reveal them. Target opponent chooses one. Put that card into your hand and the rest into your graveyard. Then shuffle.

Finale of Devastation

Search your library and/or graveyard for a creature card with mana value X or less and put it onto the battlefield. If you search your library this way, shuffle. If X is 10 or more, creatures you control get +X/+X and gain haste until end of turn.

Worldly Tutor

Search your library for a creature card, reveal it, then shuffle and put the card on top.

Counterspell

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Chalk Outline

Whenever one or more creature cards leave your graveyard, create a 2/2 white and blue Detective creature token, then investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Desecrated Tomb

Whenever one or more creature cards leave your graveyard, create a 1/1 black Bat creature token with flying.

Slogurk, the Overslime

Trample
Whenever a land card is put into your graveyard from anywhere, put a +1/+1 counter on Slogurk, the Overslime.
Remove three +1/+1 counters from Slogurk: Return it to its owner's hand.
When Slogurk leaves the battlefield, return up to three target land cards from your graveyard to your hand.

Willow Geist

Trample
Whenever one or more cards leave your graveyard, put a +1/+1 counter on Willow Geist.
When Willow Geist dies, you gain life equal to its power.

Zellix, Sanity Flayer

Hive Mind — Whenever a player mills one or more creature cards, you create a 1/1 black Horror creature token.
{1}, {T}: Target player mills three cards.
Choose a Background (You can have a Background as a second commander.)

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Froghemoth

Trample, haste
Whenever Froghemoth deals combat damage to a player, exile up to that many target cards from their graveyard. Put a +1/+1 counter on Froghemoth for each creature card exiled this way. You gain 1 life for each noncreature card exiled this way.

Arcane Adaptation

As Arcane Adaptation enters, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Mana Drain

Counter target spell. At the beginning of your next main phase, add an amount of {C} equal to that spell's mana value.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Benevolent Geist

Flying
Noncreature spells you control can't be countered.
If Benevolent Geist would be put into a graveyard from anywhere, exile it instead.

Malevolent Hermit

{U}, Sacrifice Malevolent Hermit: Counter target noncreature spell unless its controller pays {3}.
Disturb {2}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Malevolent Hermit // Benevolent Geist

Petty Theft

Return target nonland permanent an opponent controls to its owner's hand.

Brazen Borrower

Flash
Flying
Brazen Borrower can block only creatures with flying.

Brazen Borrower // Petty Theft

Tribute Mage

When Tribute Mage enters, you may search your library for an artifact card with mana value 2, reveal that card, put it into your hand, then shuffle.