Frilled Mystic

Flash
When this creature enters, you may counter target spell.

Chronic Flooding

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

Hinterland Harbor

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

Millikin

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

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Mulch

Reveal the top four cards of your library. Put all land cards revealed this way into your hand and the rest into your graveyard.

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.

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.)

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.)

Species Gorger

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

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.

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.)

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

Novijen, Heart of Progress

{T}: Add {C}.
{G}{U}, {T}: Put a +1/+1 counter on each creature that entered this turn.

Papercraft Decoy

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

Mystic Snake

Flash
When this creature enters, counter target spell.

Leapfrog

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

Jace's Erasure

Whenever you draw a card, you may have target player mill a card.

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}.

Exotic Orchard

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

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.)

Slogurk, the Overslime

Trample
Whenever a land card is put into your graveyard from anywhere, put a +1/+1 counter on Slogurk.
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.

Explore

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

Azusa, Lost but Seeking

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

Jace, the Perfected Mind

Compleated ({U/P} can be paid with {U} or 2 life. If life was paid, this planeswalker enters with two fewer loyalty counters.)
+1: Until your next turn, up to one target creature gets -3/-0.
−2: Target player mills three cards. Then if a graveyard has twenty or more cards in it, you draw three cards. Otherwise, you draw a card.
−X: Target player mills three times X cards.

Island

Lotus Cobra

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

Crawling Infestation

At the beginning of your upkeep, you may mill two cards. (You may put the top two cards of your library into your graveyard.)
Whenever one or more creature cards are put into your graveyard from anywhere during your turn, create a 1/1 green Insect creature token. This ability triggers only once each turn.

Fact or Fiction

Reveal the top five cards of your library. An opponent separates those cards into two piles. Put one pile into your hand and the other into your graveyard.

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.

Moritte of the Frost

Changeling (This card is every creature type.)
You may have Moritte enter as a copy of a permanent you control, except it's legendary and snow in addition to its other types and, if it's a creature, it enters with two additional +1/+1 counters on it and has changeling.

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.

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.

Crawling Sensation

At the beginning of your upkeep, you may mill two cards. (You may put the top two cards of your library into your graveyard.)
Whenever one or more land cards are put into your graveyard from anywhere for the first time each turn, create a 1/1 green Insect creature token.

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.)

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.)

Amoeboid Changeling

Changeling (This card is every creature type.)
{T}: Target creature gains all creature types until end of turn.
{T}: Target creature loses all creature types until end of turn.

Thassa's Oracle

When this creature 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.)

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.

Frogmite

Affinity for artifacts (This spell costs {1} less to cast for each artifact you control.)

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

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.

Croakid Amphibonaut

This creature has flying as long as you control a stickered permanent.

Temple of the False God

{T}: Add {C}{C}. Activate only if you control five or more lands.

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.

Whiptongue Frog

{U}: This creature gains flying until end of turn.

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.

Druidic Ritual

You may mill three cards. Then return up to one creature card and up to one land card from your graveyard to your hand. (To mill a card, put the top card of your library into your graveyard.)

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.

Wand of Vertebrae

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

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Flooded Grove

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

Fabled Passage

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Chub Toad

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

Counterspell

Spore Frog

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

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.

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}.

Jade Avenger

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

Growth Spiral

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

Kasmina's Transmutation

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

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.)

Hedron Crab

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

Rampant Growth

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

Tamiyo, Collector of Tales

Spells and abilities your opponents control can't cause you to discard cards or sacrifice permanents.
+1: Choose a nonland card name, then reveal the top four cards of your library. Put all cards with the chosen name from among them into your hand and the rest into your graveyard.
−3: Return target card from your graveyard to your hand.

Thornwood Falls

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

Deranged Assistant

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}.

Excavating Anurid

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

Masked Vandal

Changeling (This card is every creature type.)
When this creature enters, you may exile a creature card from your graveyard. If you do, exile target artifact or enchantment an opponent controls.

Bloated Toad

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

Reflections of Littjara

As this enchantment enters, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Command Tower

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

Frog Tongue

Enchant creature
When this Aura enters, draw a card.
Enchanted creature has reach. (It can block creatures with flying.)

Forest

Turn to Frog

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

Botanical Sanctum

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

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.

Simic Signet

Steeple Creeper

{3}{U}: This creature gains flying until end of turn.

Druid Class

(Gain the next level as a sorcery to add its ability.)
Landfall — Whenever a land you control enters, you gain 1 life.
{2}{G}: Level 2
You may play an additional land on each of your turns.
{4}{G}: Level 3
When this Class becomes level 3, target land you control becomes a creature with haste and "This creature's power and toughness are each equal to the number of lands you control." It's still a land.