Prowling Serpopard

This spell can't be countered.
Creature spells you control can't be countered.

Impact Tremors

Whenever a creature enters the battlefield under your control, Impact Tremors deals 1 damage to each opponent.

Garrison Cat

When Garrison Cat dies, create a 1/1 white Human Soldier creature token.

Temple of Triumph

Temple of Triumph enters the battlefield tapped.
When Temple of Triumph enters the battlefield, scry 1.
{T}: Add {R} or {W}.

Jedit Ojanen of Efrava

Forestwalk (This creature can't be blocked as long as defending player controls a Forest.)
Whenever Jedit Ojanen of Efrava attacks or blocks, create a 2/2 green Cat Warrior creature token with forestwalk.

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

Selfless Savior

Sacrifice Selfless Savior: Another target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Plains

Pride Sovereign

Pride Sovereign gets +1/+1 for each other Cat you control.
{W}, {T}, Exert Pride Sovereign: Create two 1/1 white Cat creature tokens with lifelink. (An exerted creature won't untap during your next untap step.)

Tangled Vale

Tangled Vale enters the battlefield tapped.
{T}: Add {G}.

Tangled Florahedron

Tangled Florahedron // Tangled Vale

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.

Secluded Steppe

Secluded Steppe enters the battlefield tapped.
{T}: Add {W}.
Cycling {W} ({W}, Discard this card: Draw a card.)

Fire-Belly Changeling

Changeling (This card is every creature type.)
{R}: Fire-Belly Changeling gets +1/+0 until end of turn. Activate no more than twice each turn.

Felidar Retreat

Landfall — Whenever a land enters the battlefield under your control, choose one —
• Create a 2/2 white Cat Beast creature token.
• Put a +1/+1 counter on each creature you control. Those creatures gain vigilance until end of turn.

Animal Sanctuary

{T}: Add {C}.
{2}, {T}: Put a +1/+1 counter on target Bird, Cat, Dog, Goat, Ox, or Snake.

Soul Warden

Whenever another creature enters the battlefield, you gain 1 life.

Wild Nacatl

Wild Nacatl gets +1/+1 as long as you control a Mountain.
Wild Nacatl gets +1/+1 as long as you control a Plains.

Emeria, Shattered Skyclave

As Emeria, Shattered Skyclave enters the battlefield, you may pay 3 life. If you don't, it enters the battlefield tapped.
{T}: Add {W}.

Emeria's Call

Create two 4/4 white Angel Warrior creature tokens with flying. Non-Angel creatures you control gain indestructible until your next turn.

Emeria's Call // Emeria, Shattered Skyclave

King of the Pride

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Rootborn Defenses

Populate. Creatures you control gain indestructible until end of turn. (To populate, create a token that's a copy of a creature token you control.)

Khalni Territory

Khalni Territory enters the battlefield tapped.
{T}: Add {G}.

Khalni Ambush

Target creature you control fights target creature you don't control. (Each deals damage equal to its power to the other.)

Khalni Ambush // Khalni Territory

Bala Ged Sanctuary

Bala Ged Sanctuary enters the battlefield tapped.
{T}: Add {G}.

Bala Ged Recovery

Return target card from your graveyard to your hand.

Bala Ged Recovery // Bala Ged Sanctuary

Intangible Virtue

Creature tokens you control get +1/+1 and have vigilance.

Boros Guildgate

Boros Guildgate enters the battlefield tapped.
{T}: Add {R} or {W}.

Feline Sovereign

Other Cats you control get +1/+1 and have protection from Dogs.
Whenever one or more Cats you control deal combat damage to a player, destroy up to one target artifact or enchantment that player controls.

Second Harvest

For each token you control, create a token that's a copy of that permanent.

Selesnya Guildgate

Selesnya Guildgate enters the battlefield tapped.
{T}: Add {G} or {W}.

Cubwarden

Mutate {2}{W}{W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Lifelink
Whenever this creature mutates, create two 1/1 white Cat creature tokens with lifelink.

Mountain

Mentor of the Meek

Whenever another creature with power 2 or less enters the battlefield under your control, you may pay {1}. If you do, draw a card.

Ondu Skyruins

Ondu Skyruins enters the battlefield tapped.
{T}: Add {W}.

Ondu Inversion

Ondu Inversion // Ondu Skyruins

Impostor of the Sixth Pride

Changeling (This card is every creature type.)

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Pledge of Unity

Put a +1/+1 counter on each creature you control. You gain 1 life for each creature you control.

Sejiri Glacier

Sejiri Glacier enters the battlefield tapped.
{T}: Add {W}.

Sejiri Shelter

Target creature you control gains protection from the color of your choice until end of turn.

Sejiri Shelter // Sejiri Glacier

Isamaru, Hound of Konda

Sol Ring

Forgotten Cave

Forgotten Cave enters the battlefield tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Gruul Guildgate

Gruul Guildgate enters the battlefield tapped.
{T}: Add {R} or {G}.

Gavony Township

{T}: Add {C}.
{2}{G}{W}, {T}: Put a +1/+1 counter on each creature you control.

Loam Lion

Loam Lion gets +1/+2 as long as you control a Forest.

Igneous Cur

{1}{R}: Igneous Cur gets +2/+0 until end of turn.

Hour of Reckoning

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy all nontoken creatures.

Raid Bombardment

Whenever a creature you control with power 2 or less attacks, Raid Bombardment deals 1 damage to the player or planeswalker that creature is attacking.

Pack Leader

Other Dogs you control get +1/+1.
Whenever Pack Leader attacks, prevent all combat damage that would be dealt this turn to Dogs you control.

Barrier Breach

Exile up to three target enchantments.
Cycling {2} ({2}, Discard this card: Draw a card.)

Temple of Abandon

Temple of Abandon enters the battlefield tapped.
When Temple of Abandon enters the battlefield, scry 1.
{T}: Add {R} or {G}.

Regal Caracal

Other Cats you control get +1/+1 and have lifelink.
When Regal Caracal enters the battlefield, create two 1/1 white Cat creature tokens with lifelink.

Boros Charm

Choose one —
• Boros Charm deals 4 damage to target player or planeswalker.
• Permanents you control gain indestructible until end of turn.
• Target creature gains double strike until end of turn.

Bronzehide Lion

{G}{W}: Bronzehide Lion gains indestructible until end of turn.
When Bronzehide Lion dies, return it to the battlefield. It's an Aura enchantment with enchant creature you control and "{G}{W}: Enchanted creature gains indestructible until end of turn," and it loses all other abilities.

Tranquil Thicket

Tranquil Thicket enters the battlefield tapped.
{T}: Add {G}.
Cycling {G} ({G}, Discard this card: Draw a card.)

Regal Leosaur

Mutate {1}{R/W}{R/W} (If you cast this spell for its mutate cost, put it over or under target non-Human creature you own. They mutate into the creature on top plus all abilities from under it.)
Whenever this creature mutates, other creatures you control get +2/+1 until end of turn.

Migration Path

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.
Cycling {2} ({2}, Discard this card: Draw a card.)

Healer of the Pride

Whenever another creature enters the battlefield under your control, you gain 2 life.

Command Tower

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

Resolute Watchdog

Defender
{1}, Sacrifice Resolute Watchdog: Target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Goblin War Drums

Creatures you control have menace. (They can't be blocked except by two or more creatures.)

Alpine Houndmaster

When Alpine Houndmaster enters the battlefield, you may search your library for a card named Alpine Watchdog and/or a card named Igneous Cur, reveal them, put them into your hand, then shuffle.
Whenever Alpine Houndmaster attacks, it gets +X/+0 until end of turn, where X is the number of other attacking creatures.

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Prowling Felidar

Vigilance
Landfall — Whenever a land enters the battlefield under your control, put a +1/+1 counter on Prowling Felidar.

Titanic Ultimatum

Until end of turn, creatures you control get +5/+5 and gain first strike, trample, and lifelink.

Kaheera, the Orphanguard

Companion — Each creature card in your starting deck is a Cat, Elemental, Nightmare, Dinosaur, or Beast card. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Vigilance
Each other creature you control that's a Cat, Elemental, Nightmare, Dinosaur, or Beast gets +1/+1 and has vigilance.

Alpine Watchdog

Vigilance (Attacking doesn't cause this creature to tap.)

Felidar Cub

Sacrifice Felidar Cub: Destroy target enchantment.

Keeper of Fables

Whenever one or more non-Human creatures you control deal combat damage to a player, draw a card.

Forest

Trusty Retriever

When Trusty Retriever enters the battlefield, choose one —
• Put a +1/+1 counter on Trusty Retriever.
• Return target artifact or enchantment card from your graveyard to your hand.

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.

Generous Gift

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

Jungle Shrine

Jungle Shrine enters the battlefield tapped.
{T}: Add {R}, {G}, or {W}.

Temple of Plenty

Temple of Plenty enters the battlefield tapped.
When Temple of Plenty enters the battlefield, scry 1.
{T}: Add {G} or {W}.

Rin and Seri, Inseparable

Whenever you cast a Dog spell, create a 1/1 green Cat creature token.
Whenever you cast a Cat spell, create a 1/1 white Dog creature token.
{R}{G}{W}, {T}: Rin and Seri, Inseparable deals damage to any target equal to the number of Dogs you control. You gain life equal to the number of Cats you control.

Valakut Stoneforge

Valakut Stoneforge enters the battlefield tapped.
{T}: Add {R}.

Valakut Awakening

Put any number of cards from your hand on the bottom of your library, then draw that many cards plus one.

Valakut Awakening // Valakut Stoneforge

Make a Stand

Creatures you control get +1/+0 and gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Attended Healer

Whenever you gain life for the first time each turn, create a 1/1 white Cat creature token.
{2}{W}: Another target Cleric gains lifelink until end of turn.

Qasali Slingers

Reach
Whenever Qasali Slingers or another Cat enters the battlefield under your control, you may destroy target artifact or enchantment.

Essence Warden

Ferocious Tigorilla

Ferocious Tigorilla enters the battlefield with your choice of a trample counter or a menace counter on it. (A creature with menace can't be blocked except by two or more creatures.)

Explosive Vegetation

Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Universal Automaton

Ajani's Welcome

Whenever a creature enters the battlefield under your control, you gain 1 life.

Vivien, Champion of the Wilds

You may cast creature spells as though they had flash.
+1: Until your next turn, up to one target creature gains vigilance and reach.
−2: Look at the top three cards of your library. Exile one face down and put the rest on the bottom of your library in any order. For as long as it remains exiled, you may look at that card and you may cast it if it's a creature spell.

Release the Dogs

Create four 1/1 white Dog creature tokens.

Leonin Warleader

Whenever Leonin Warleader attacks, create two 1/1 white Cat creature tokens with lifelink that are tapped and attacking.

Trove Warden

Vigilance
Landfall — Whenever a land enters the battlefield under your control, exile target permanent card with mana value 3 or less from your graveyard.
When Trove Warden dies, put each permanent card exiled with it onto the battlefield under the control of that card's owner.

Woodland Changeling

Mirror Entity

Changeling (This card is every creature type.)
{X}: Until end of turn, creatures you control have base power and toughness X/X and gain all creature types.

Felidar Sovereign

Vigilance, lifelink
At the beginning of your upkeep, if you have 40 or more life, you win the game.