Plaxcaster Frogling

Graft 3 (This creature enters the battlefield with three +1/+1 counters on it. Whenever another creature enters the battlefield, 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.)

Burrog Befuddler

Flash
When Burrog Befuddler enters the battlefield, target creature an opponent controls gets -1/-0 until end of turn.

Crocanura

Reach (This creature can block creatures with flying.)
Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Excavating Anurid

When Excavating Anurid enters the battlefield, you may sacrifice a land. If you do, draw a card.
Threshold — As long as seven or more cards are in your graveyard, Excavating Anurid gets +1/+1 and has vigilance.

Steeple Creeper

{3}{U}: Steeple Creeper gains flying until end of turn.

Explore

You may play an additional land this turn.
Draw a card.

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.

Chameleon Colossus

Changeling (This card is every creature type.)
Protection from black
{2}{G}{G}: Chameleon Colossus gets +X/+X until end of turn, where X is its power.

Thought Scour

Target player mills two cards.
Draw a card.

Hedron Crab

Landfall — Whenever a land enters the battlefield under your control, target player mills three cards.

Game-Trail Changeling

Changeling (This card is every creature type.)
Trample

Wings of Velis Vel

Changeling (This card is every creature type.)
Until end of turn, target creature has base power and toughness 4/4, gains all creature types, and gains flying.

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.)

Haze Frog

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

Turtleshell Changeling

Changeling (This card is every creature type.)
{1}{U}: Switch Turtleshell Changeling's power and toughness until end of turn.

Guardian Gladewalker

Changeling (This card is every creature type.)
When Guardian Gladewalker enters the battlefield, put a +1/+1 counter on target creature.

Frog Tongue

Enchant creature
When Frog Tongue enters the battlefield, draw a card.
Enchanted creature has reach. (It can block creatures with flying.)

Bloated Toad

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

Anurid Barkripper

Threshold — Anurid Barkripper gets +2/+2 as long as seven or more cards are in your graveyard.

Omnibian

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

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.)

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.

Homarid Explorer

When Homarid Explorer enters the battlefield, target player mills four cards.

Leapfrog

Leapfrog has flying as long as you've cast an instant or sorcery spell this turn.

Spore Frog

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

Galloping Lizrog

Trample
When Galloping Lizrog enters the battlefield, 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 Galloping Lizrog.

Kindred Summons

Choose a creature type. Reveal cards from the top of your library until you reveal X creature cards of the chosen type, where X is the number of creatures you control of that type. Put those cards onto the battlefield, then shuffle the rest of the revealed cards into your library.

Sakura-Tribe Elder

Sacrifice Sakura-Tribe Elder: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Growth Spiral

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

Jade Avenger

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

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.

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.

Bloodline Pretender

Changeling (This card is every creature type.)
As Bloodline Pretender enters the battlefield, choose a creature type.
Whenever another creature of the chosen type enters the battlefield under your control, put a +1/+1 counter on Bloodline Pretender.

Biomass Mutation

Creatures you control have base power and toughness X/X 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.)

Incongruity

Exile target creature. That creature's controller creates a 3/3 green Frog Lizard creature token.

Incubation

Look at the top five cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Incubation // Incongruity

Littjara Glade-Warden

Changeling (This card is every creature type.)
{2}{G}, {T}, Exile a creature card from your graveyard: Put two +1/+1 counters on target creature. Activate only as a sorcery.

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.