Arctic Wolves

Cumulative upkeep {2} (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)
When Arctic Wolves enters, draw a card.

Lab Rats

Buyback {4} (You may pay an additional {4} as you cast this spell. If you do, put this card into your hand as it resolves.)
Create a 1/1 black Rat creature token.

Bayou Dragonfly

Flying; swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)

Leaping Lizard

{1}{G}: Leaping Lizard gets -0/-1 and gains flying until end of turn.

Carrion Rats

Whenever Carrion Rats attacks or blocks, any player may exile a card from their graveyard. If a player does, Carrion Rats assigns no combat damage this turn.

Karoo

Karoo enters tapped.
When Karoo enters, sacrifice it unless you return an untapped Plains you control to its owner's hand.
{T}: Add {C}{W}.

Plague Rats

Plague Rats's power and toughness are each equal to the number of creatures named Plague Rats on the battlefield.

Deepwood Wolverine

Whenever Deepwood Wolverine becomes blocked, it gets +2/+0 until end of turn.

Ferocious Pup

When Ferocious Pup enters, create a 2/2 green Wolf creature token.

Dream Thrush

Flying
{T}: Target land becomes the basic land type of your choice until end of turn.

Bay Falcon

Rambunctious Mutt

When Rambunctious Mutt enters, destroy target artifact or enchantment an opponent controls.

Circling Vultures

Flying
You may discard Circling Vultures any time you could cast an instant.
At the beginning of your upkeep, sacrifice Circling Vultures unless you exile the top creature card of your graveyard.

Courier Hawk

Fire Ants

{T}: Fire Ants deals 1 damage to each other creature without flying.

Wild Growth

Enchant land
Whenever enchanted land is tapped for mana, its controller adds an additional {G}.

Messenger Falcons

Flying
When Messenger Falcons enters, draw a card.

Kingfisher

Flying
When Kingfisher dies, draw a card.

Glowing Anemone

When Glowing Anemone enters, you may return target land to its owner's hand.

Storm Crow

Flying (This creature can't be blocked except by creatures with flying or reach.)

Giant Shark

Giant Shark can't attack unless defending player controls an Island.
Whenever Giant Shark blocks or becomes blocked by a creature that has been dealt damage this turn, Giant Shark gets +2/+0 and gains trample until end of turn.
When you control no Islands, sacrifice Giant Shark.

Woolly Mammoths

Woolly Mammoths has trample as long as you control a snow land.

Highland Game

When Highland Game dies, you gain 2 life.

Rootwalla

{1}{G}: Rootwalla gets +2/+2 until end of turn. Activate only once each turn.

Rustspore Ram

When Rustspore Ram enters, destroy target Equipment.

Vexing Gull

Rabid Rats

{T}: Target blocking creature gets -1/-1 until end of turn.

Brushwagg

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

Squirrel Mob

Squirrel Mob gets +1/+1 for each other Squirrel on the battlefield.

Goliath Beetle

Owl Familiar

Flying
When Owl Familiar enters, draw a card, then discard a card.

Caribou Range

Enchant land you control
Enchanted land has "{W}{W}, {T}: Create a 0/1 white Caribou creature token."
Sacrifice a Caribou token: You gain 1 life.

Hyalopterous Lemure

{0}: Hyalopterous Lemure gets -1/-0 and gains flying until end of turn.

Carrion Grub

Carrion Grub gets +X/+0, where X is the greatest power among creature cards in your graveyard.
When Carrion Grub enters, mill four cards. (Put the top four cards of your library into your graveyard.)

Birds of Paradise

Locust Swarm

Flying
{G}: Regenerate Locust Swarm.
{G}: Untap Locust Swarm. Activate only once each turn.

Killer Whale

{U}: Killer Whale gains flying until end of turn.

Insidious Bookworms

When Insidious Bookworms dies, you may pay {1}{B}. If you do, target player discards a card at random.

Rhystic Study

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

Dire Wolves

Dire Wolves has banding as long as you control a Plains. (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Hyena Pack

Howling Wolf

When Howling Wolf enters, you may search your library for up to three cards named Howling Wolf, reveal them, put them into your hand, then shuffle.

Elephant Graveyard

{T}: Add {C}.
{T}: Regenerate target Elephant.

Fledgling Osprey

Fledgling Osprey has flying as long as it's enchanted.

Timber Wolves

Banding (Any creatures with banding, and up to one without, can attack in a band. Bands are blocked as a group. If any creatures with banding you control are blocking or being blocked by a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by or is blocking.)

Pit Scorpion

Whenever Pit Scorpion deals damage to a player, that player gets a poison counter. (A player with ten or more poison counters loses the game.)

Mountain Yeti

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)
Protection from white

Raging Gorilla

Whenever Raging Gorilla blocks or becomes blocked, it gets +2/-2 until end of turn.

Pillarfield Ox

Killer Bees

Flying
{G}: Killer Bees gets +1/+1 until end of turn.

Bog Rats

Relentless Rats

Relentless Rats gets +1/+1 for each other creature on the battlefield named Relentless Rats.
A deck can have any number of cards named Relentless Rats.

King Crab

{1}{U}, {T}: Put target green creature on top of its owner's library.

Man-o'-War

When Man-o'-War enters, return target creature to its owner's hand.

Wolverine Pack

Rampage 2 (Whenever this creature becomes blocked, it gets +2/+2 until end of turn for each creature blocking it beyond the first.)

Army Ants

{T}, Sacrifice a land: Destroy target land.

Pestilence Rats

Pestilence Rats's power is equal to the number of other Rats on the battlefield. (For example, as long as there are two other Rats on the battlefield, Pestilence Rats's power and toughness are 2/3.)

Gang of Elk

Whenever Gang of Elk becomes blocked, it gets +2/+2 until end of turn for each creature blocking it.

Basking Rootwalla

{1}{G}: Basking Rootwalla gets +2/+2 until end of turn. Activate only once each turn.
Madness {0} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Gibbering Hyenas

Gibbering Hyenas can't block black creatures.

Charging Rhino

Charging Rhino can't be blocked by more than one creature.

Marsh Viper

Whenever Marsh Viper deals damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)

Giant Octopus

Screaming Seahawk

Flying
When Screaming Seahawk enters, you may search your library for a card named Screaming Seahawk, reveal it, put it into your hand, then shuffle.

Robber Fly

Flying
Whenever Robber Fly becomes blocked, defending player discards all the cards in their hand, then draws that many cards.

Mountain Goat

Mountainwalk (This creature can't be blocked as long as defending player controls a Mountain.)

Dakmor Bat

Charging Badger

Karoo Meerkat

Coveted Peacock

Flying
Whenever Coveted Peacock attacks, you may goad target creature defending player controls. (Until your next turn, that creature attacks each combat if able and attacks a player other than you if able.)

Algae Gharial

Shroud (This creature can't be the target of spells or abilities.)
Whenever another creature dies, you may put a +1/+1 counter on Algae Gharial.

Reckless Pangolin

Whenever Reckless Pangolin attacks, it gets +1/+1 until end of turn.

Skyclave Squid

Defender
Landfall — Whenever a land you control enters, Skyclave Squid can attack this turn as though it didn't have defender.

Utopia Sprawl

Enchant Forest
As Utopia Sprawl enters, choose a color.
Whenever enchanted Forest is tapped for mana, its controller adds an additional one mana of the chosen color.

Sea Eagle

Lurking Crocodile

Bloodthirst 1 (If an opponent was dealt damage this turn, this creature enters with a +1/+1 counter on it.)
Islandwalk (This creature can't be blocked as long as defending player controls an Island.)

Yoked Ox

Bloated Toad

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

Deadly Recluse

Reach (This creature can block creatures with flying.)
Deathtouch (Any amount of damage this deals to a creature is enough to destroy it.)

Rabid Wombat

Vigilance
Rabid Wombat gets +2/+2 for each Aura attached to it.

Giant Turtle

Giant Turtle can't attack if it attacked during your last turn.

Python

Raging Cougar

Thieving Otter

Whenever Thieving Otter deals damage to an opponent, draw a card.

Swarm of Rats

Swarm of Rats's power is equal to the number of Rats you control.

Artificer's Assistant

Flying
Whenever you cast a historic spell, scry 1. (Artifacts, legendaries, and Sagas are historic. To scry 1, look at the top card of your library, then you may put that card on the bottom.)

Land Leeches

Dawntreader Elk

{G}, Sacrifice Dawntreader Elk: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Joven's Ferrets

Whenever Joven's Ferrets attacks, it gets +0/+2 until end of turn.
At end of combat, tap all creatures that blocked Joven's Ferrets this turn. They don't untap during their controller's next untap step.

Fog of Gnats

Clinging Anemones

Defender
Evolve (Whenever a creature enters under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)

Ravenous Rats

When Ravenous Rats enters, target opponent discards a card.

Graceful Antelope

Plainswalk (This creature can't be blocked as long as defending player controls a Plains.)
Whenever Graceful Antelope deals combat damage to a player, you may have target land become a Plains until Graceful Antelope leaves the battlefield.

Giant Ox

Giant Ox crews Vehicles using its toughness rather than its power.

Wild Dogs

At the beginning of your upkeep, if a player has more life than each other player, the player with the most life gains control of Wild Dogs.
Cycling {2} ({2}, Discard this card: Draw a card.)

Snow Hound

{1}, {T}: Return Snow Hound and target green or blue creature you control to their owner's hand.

Swarmyard

{T}: Add {C}.
{T}: Regenerate target Insect, Rat, Spider, or Squirrel. (The next time it would be destroyed, instead tap it, remove it from combat, and heal all damage on it.)

Spiny Starfish

{U}: Regenerate Spiny Starfish.
At the beginning of each end step, if Spiny Starfish regenerated this turn, create a 0/1 blue Starfish creature token for each time it regenerated this turn.

Charmed Stray

Lifelink
When Charmed Stray enters, put a +1/+1 counter on each other creature you control named Charmed Stray.

Jodah, Archmage Eternal

Flying
You may pay {W}{U}{B}{R}{G} rather than pay the mana cost for spells you cast.

Young Wolf

Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Solitary Camel

Solitary Camel has lifelink as long as you control a Desert or there is a Desert card in your graveyard. (Damage dealt by this creature also causes you to gain that much life.)

Mesa Chicken

Stand up, Flap your arms, Cluck like a chicken: Mesa Chicken gains flying until end of turn.

Crypt Rats

{X}: Crypt Rats deals X damage to each creature and each player. Spend only black mana on X.

Giant Oyster

You may choose not to untap Giant Oyster during your untap step.
{T}: For as long as Giant Oyster remains tapped, target tapped creature doesn't untap during its controller's untap step, and at the beginning of each of your draw steps, put a -1/-1 counter on that creature. When Giant Oyster leaves the battlefield or becomes untapped, remove all -1/-1 counters from the creature.

Pygmy Hippo

Whenever Pygmy Hippo attacks and isn't blocked, you may have defending player activate a mana ability of each land they control and lose all unspent mana. If you do, Pygmy Hippo assigns no combat damage this turn and at the beginning of your next main phase this turn, you add an amount of {C} equal to the amount of mana that player lost this way.

Bull Elephant

When Bull Elephant enters, sacrifice it unless you return two Forests you control to their owner's hand.

Rabid Wolverines

Whenever Rabid Wolverines becomes blocked by a creature, Rabid Wolverines gets +1/+1 until end of turn.

Bellowing Elk

As long as you had another creature enter the battlefield under your control this turn, Bellowing Elk has trample and indestructible.

Wolf Pack

You may have Wolf Pack assign its combat damage as though it weren't blocked.