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."

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.

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.)

Kasmina's Transmutation

Enchant creature
Enchanted creature loses all abilities and has base power and toughness 1/1.

Nebelgast Herald

Flash
Flying
Whenever this creature or another Spirit you control enters, tap target creature an opponent controls.

Growth Spiral

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

Papercraft Decoy

When this creature leaves the battlefield, you may pay {2}. If you do, draw a card.

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.

Rampant Growth

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

Studious First-Year

This creature enters prepared. (While it's prepared, you may cast a copy of its spell. Doing so unprepares it.)

Studious First-Year // Rampant Growth

Mirror of Life Trapping

Whenever a creature enters, if it was cast, exile it, then return all other permanent cards exiled with this artifact to the battlefield under their owners' control.

Lifecrafter's Bestiary

At the beginning of your upkeep, scry 1.
Whenever you cast a creature spell, you may pay {G}. If you do, draw a card.

Jubilation

When this creature enters, creatures you control get +2/+2 and gain trample until end of turn.
Encore {7}{G}{G} ({7}{G}{G}, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Pond Prophet

Burrog Befuddler

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, target creature an opponent controls gets -1/-0 until end of turn.

Bellowing Crier

When this creature enters, draw a card, then discard a card.

Run Away Together

Choose two target creatures controlled by different players. Return those creatures to their owners' hands.

Clifftop Lookout

Reach
When this creature enters, reveal cards from the top of your library until you reveal a land card. Put that card onto the battlefield tapped and the rest on the bottom of your library in a random order.

Sunshower Druid

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

Arcane Signet

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

Valley Mightcaller

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

Skyskipper Duo

Flying
When this creature enters, exile up to one other target creature you control. Return it to the battlefield under its owner's control at the beginning of the next end step.

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.)

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.

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

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.

Sol Ring

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.

Wear Down

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.)
Destroy target artifact or enchantment. If the gift was promised, instead destroy two target artifacts and/or enchantments.

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.

Fisher's Talent

(Gain the next level as a sorcery to add its ability.)
At the beginning of your upkeep, look at the top card of your library. You may reveal it if it's a land card. Create a 1/1 blue Fish creature token if you revealed it this way. Then draw a card.
{G}{U}: Level 2
If you would create a Fish token, create a 3/3 blue Shark creature token instead.
{2}{G}{U}: Level 3
If you would create a Shark token, create an 8/8 blue Octopus creature token instead.

Waterspout Warden

Whenever this creature attacks, if another creature entered the battlefield under your control this turn, this creature gains flying until end of turn.

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.

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.

Splash Lasher

Offspring {1}{U} (You may pay an additional {1}{U} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
When this creature enters, tap up to one target creature and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Textbook Tabulator

Increment (Whenever you cast a spell, if the amount of mana you spent is greater than this creature's power or toughness, put a +1/+1 counter on this creature.)
When this creature enters, 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.)

Island

Octomancer

Gift an Octopus (You may promise an opponent a gift as you cast this spell. If you do, when it enters, they create an 8/8 blue Octopus creature token.)
At the beginning of each end step, create a token that's a copy of target creature token that entered the battlefield this turn.

Greenwarden of Murasa

When this creature enters, you may return target card from your graveyard to your hand.
When this creature dies, you may exile it. If you do, return target card from your graveyard to your hand.

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.

Berta, Wise Extrapolator

Increment (Whenever you cast a spell, if the amount of mana you spent is greater than this creature's power or toughness, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Berta, add one mana of any color.
{X}, {T}: Create a 0/0 green and blue Fractal creature token and put X +1/+1 counters on it.

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.

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.

Forest

Verdant Sun's Avatar

Whenever this creature or another creature you control enters, you gain life equal to that creature's toughness.

Galloping Lizrog

Trample
When this creature enters, you may remove any number of +1/+1 counters from among creatures you control. If you do, put twice that many +1/+1 counters on this creature.

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.

Evacuation

Return all creatures to their owners' hands.

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.

Sugar Coat

Flash
Enchant creature or Food
Enchanted permanent is a colorless Food artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life" and loses all other card types and abilities.

Warden of the Grove

At the beginning of your end step, put a +1/+1 counter on this creature.
Whenever another nontoken creature you control enters, it endures X, where X is the number of counters on this creature. (Put X +1/+1 counters on the creature that entered or create an X/X white Spirit creature token.)

Fractal Mascot

Trample
When this creature enters, tap target creature an opponent controls. Put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

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.)

This Town Ain't Big Enough

This spell costs {3} less to cast if it targets a permanent you control.
Return up to two target nonland permanents to their owners' hands.

Bane of Progress

When this creature enters, destroy all artifacts and enchantments. Put a +1/+1 counter on this creature for each permanent destroyed this way.

Turn to Frog

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

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.

Tyranid Prime

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.)
Synapse Creature — Other creatures you control have evolve.

Virulent Emissary

Deathtouch
Whenever another creature you control enters, you gain 1 life.

Splash Portal

Exile target creature you control, then return it to the battlefield under its owner's control. If that creature is a Bird, Frog, Otter, or Rat, draw a card.

Stickytongue Sentinel

Reach
When this creature enters, return up to one other target permanent you control to its owner's hand.

Jade Avenger

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

Gossip's Talent

(Gain the next level as a sorcery to add its ability.)
Whenever a creature you control enters, surveil 1.
{1}{U}: Level 2
Whenever you attack, target attacking creature with power 3 or less can't be blocked this turn.
{3}{U}: Level 3
Whenever a creature you control deals combat damage to a player, you may exile it, then return it to the battlefield under its owner's control.

Simic Signet

Poison Dart Frog

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

Dinosaur Egg

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.)
When this creature dies, you may discover X, where X is its toughness.

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.