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.

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.

Valley Mightcaller

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

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.

Laboratory Maniac

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

Croaking Counterpart

Create a token that's a copy of target non-Frog creature, except it's a 1/1 green Frog.
Flashback {3}{G}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Reclamation Sage

When this creature enters, you may destroy target artifact or enchantment.

Spore Frog

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

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.

Command Tower

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

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.

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.

Millikin

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

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.

Traumatize

Target player mills half their library, rounded down.

Eternal Witness

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

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.

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.

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.

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.

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.

Talisman of Curiosity

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

Azusa, Lost but Seeking

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

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.

Pond Prophet

Exploration

You may play an additional land 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.

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.

Sunshower Druid

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

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.

Jace, Wielder of Mysteries

If you would draw a card while your library has no cards in it, you win the game instead.
+1: Target player mills two cards. Draw a card.
−8: Draw seven cards. Then if your library has no cards in it, you win the game.

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.

Stickytongue Sentinel

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

Simic Signet

Arcane Signet

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.

Omnibian

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

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.

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.