Clement, the Worrywort

Vigilance
Whenever Clement or another creature you control enters, return up to one target creature you control with lesser mana value to its owner's hand.
Frogs you control have "{T}: Add {G} or {U}. Spend this mana only to cast a creature spell."

Mesmeric Orb

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

Dreamdew Entrancer

Reach
When this creature enters, tap up to one target creature and put three stun counters on it. If you control that creature, draw two cards.

Glarb, Calamity's Augur

Deathtouch
You may look at the top card of your library any time.
You may play lands and cast spells with mana value 4 or greater from the top of your library.
{T}: Surveil 2.

Mistbreath Elder

At the beginning of your upkeep, return another creature you control to its owner's hand. If you do, put a +1/+1 counter on this creature. Otherwise, you may return this creature to its owner's hand.

Hedge Maze

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

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.

Bloated Toad

Protection from blue
Cycling {2} ({2}, Discard this card: Draw a card.)

Thought Scour

Target player mills two cards.
Draw a card.

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.

Arcane Signet

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

Sab-Sunen, Luxa Embodied

Reach, trample, indestructible
Sab-Sunen can't attack or block unless it has an even number of counters on it. (Zero is even.)
At the beginning of your first main phase, put a +1/+1 counter on Sab-Sunen. Then if it has an odd number of counters on it, draw two cards.

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.")

Hinterland Harbor

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

Long River's Pull

Gift a card (You may promise an opponent a gift as you cast this spell. If you do, they draw a card before its other effects.)
Counter target creature spell. If the gift was promised, instead counter target spell.

Treeguard Duo

When this creature enters, until end of turn, target creature you control gains vigilance and gets +X/+X, where X is the number of creatures you control.

Enter the Infinite

Draw cards equal to the number of cards in your library, then put a card from your hand on top of your library. You have no maximum hand size until your next turn.

Froghemoth

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

Poison Dart Frog

Reach
{T}: Add one mana of any color.
{2}: This creature gains deathtouch until end of turn.

Otherworldly Gaze

Surveil 3. (Look at the top three cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Codex Shredder

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

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.

Valley Mightcaller

Trample
Whenever another Frog, Rabbit, Raccoon, or Squirrel you control enters, put a +1/+1 counter on this creature.

Rampant Growth

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

Dreamroot Cascade

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

Jade Avenger

Bushido 2 (Whenever this creature blocks or becomes blocked, it gets +2/+2 until end of turn.)

Omnibian

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

Riverchurn Monument

{1}, {T}: Any number of target players each mill two cards. (Each of them puts the top two cards of their library into their graveyard.)
Exhaust — {2}{U}{U}, {T}: Any number of target players each mill cards equal to the number of cards in their graveyard. (Activate each exhaust ability only once.)

Flubs, the Fool

You may play an additional land on each of your turns.
Whenever you play a land or cast a spell, draw a card if you have no cards in hand. Otherwise, discard a card.

Sunshower Druid

When this creature enters, put a +1/+1 counter on target creature and you gain 1 life.

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.

Dream Twist

Target player mills three cards.
Flashback {1}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Command Tower

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 this creature's power, draw a card.

Could remove

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Forest

Willow Geist

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

Vineglimmer Snarl

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

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.

Polymorphist's Jest

Until end of turn, each creature target player controls loses all abilities and becomes a blue Frog with base power and toughness 1/1.

Polliwallop

Affinity for Frogs (This spell costs {1} less to cast for each Frog you control.)
Target creature you control deals damage equal to twice its power to target creature you don't control.

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.

Three Tree Scribe

Whenever this creature or another creature you control leaves the battlefield without dying, put a +1/+1 counter on target creature you control.

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.

Traumatize

Target player mills half their library, rounded down.

Nissa, Who Shakes the World

Whenever you tap a Forest for mana, add an additional {G}.
+1: Put three +1/+1 counters on up to one target noncreature land you control. Untap it. It becomes a 0/0 Elemental creature with vigilance and haste that's still a land.
−8: You get an emblem with "Lands you control have indestructible." Search your library for any number of Forest cards, put them onto the battlefield tapped, then shuffle.

Waterlogged Grove

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

Long River Lurker

Ward {1}
Other Frogs you control have ward {1}.
When this creature 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.

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}.

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. This land deals 1 damage to you.

Hedron Crab

Landfall — Whenever a land you control enters, target player mills three cards. (They put the top three cards of their library into their graveyard.)

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.

Species Gorger

At the beginning of your upkeep, return a creature you control to its owner's hand.

Counterspell

Sol Ring

Simic Ascendancy

{1}{G}{U}: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on this enchantment.
At the beginning of your upkeep, if this enchantment has twenty or more growth counters on it, you win the game.

Simic Growth Chamber

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {G}{U}.

Trollbred Guardian

{2}{G}: Adapt 2. (If this creature has no +1/+1 counters on it, put two +1/+1 counters on it.)
Each creature you control with a +1/+1 counter on it has trample.

Spore Frog

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

Haze Frog

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, prevent all combat damage that other creatures would deal this 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.

Pond Prophet

Breeding Pool

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

Murkfiend Liege

Other green creatures you control get +1/+1.
Other blue creatures you control get +1/+1.
Untap all green and/or blue creatures you control during each other player's untap step.

Rampant Frogantua

Trample
This creature gets +10/+10 for each player who has lost the game.
Whenever this creature 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.

Lightning Greaves

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

Dour Port-Mage

Whenever one or more other creatures you control leave the battlefield without dying, draw a card.
{1}{U}, {T}: Return another target creature you control to its owner's hand.

Island

Exploration

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

Deranged Assistant

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

Plaxcaster Frogling

Graft 3 (This creature enters with three +1/+1 counters on it. Whenever another creature enters, you may move a +1/+1 counter from this creature onto it.)
{2}: Target creature with a +1/+1 counter on it gains shroud until end of turn. (It can't be the target of spells or abilities.)

Omniscience

You may cast spells from your hand without paying their mana costs.

Reach
Whenever Six attacks, mill three cards. You may put a land card from among them into your hand.
During your turn, nonland permanent cards in your graveyard have retrace. (You may cast permanent cards from your graveyard by discarding a land card in addition to paying their other costs.)

Crocanura

Reach (This creature can block creatures with flying.)
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.)

Into the Flood Maw

Gift a tapped Fish (You may promise an opponent a gift as you cast this spell. If you do, they create a tapped 1/1 blue Fish creature token before its other effects.)
Return target creature an opponent controls to its owner's hand. If the gift was promised, instead return target nonland permanent an opponent controls to its owner's hand.

Laboratory Maniac

If you would draw a card while your library has no cards in it, you win the game instead.

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Tome Scour

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.)

Perpetual Timepiece

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

Lilysplash Mentor

Reach
{1}{G}{U}: Exile another target creature you control, then return it to the battlefield under its owner's control with a +1/+1 counter on it. Activate only as a sorcery.

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Thornwood Falls

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {U}.

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

Cloud of Faeries

Flying
When this creature enters, untap up to two lands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Azusa, Lost but Seeking

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

Twenty-Toed Toad

Your maximum hand size is twenty.
Whenever you attack with two or more creatures, put a +1/+1 counter on this creature and draw a card.
Whenever this creature attacks, you win the game if there are twenty or more counters on it or you have twenty or more cards in hand.