Cloud Key

As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Tribute to the World Tree

Whenever a creature enters the battlefield under your control, draw a card if its power is 3 or greater. Otherwise, put two +1/+1 counters on it.

Perplexing Test

Choose one —
• Return all creature tokens to their owners' hands.
• Return all nontoken creatures to their owners' hands.

Triumph of the Hordes

Until end of turn, creatures you control get +1/+1 and gain trample and infect. (Creatures with infect deal damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)

Colossal Majesty

At the beginning of your upkeep, if you control a creature with power 4 or greater, draw a card.

Simic Signet

Cyclonic Rift

Return target nonland permanent you don't control to its owner's hand.
Overload {6}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Sol Ring

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control.)
Equip {1}

Beast Within

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

Harrow

As an additional cost to cast this spell, sacrifice a land.
Search your library for up to two basic land cards, put them onto the battlefield, then shuffle.

Reliquary Tower

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

Shamanic Revelation

Draw a card for each creature you control.
Ferocious — You gain 4 life for each creature you control with power 4 or greater.

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. Yavimaya Coast deals 1 damage to you.

Branching Evolution

If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.

Naturalize

Rhystic Study

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

Counterspell

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Itlimoc, Cradle of the Sun

(Transforms from Growing Rites of Itlimoc.)
{T}: Add {G}.
{T}: Add {G} for each creature you control.

Growing Rites of Itlimoc

When Growing Rites of Itlimoc enters the battlefield, look at the top four 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 any order.
At the beginning of your end step, if you control four or more creatures, transform Growing Rites of Itlimoc.

Growing Rites of Itlimoc // Itlimoc, Cradle of the Sun

Mutational Advantage

Permanents you control with counters on them gain hexproof and indestructible until end of turn. Prevent all damage that would be dealt to those permanents this turn. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Rampant Growth

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

Simic Ascendancy

{1}{G}{U}: Put a +1/+1 counter on target creature you control.
Whenever one or more +1/+1 counters are put on a creature you control, put that many growth counters on Simic Ascendancy.
At the beginning of your upkeep, if Simic Ascendancy has twenty or more growth counters on it, you win the game.

Bred for the Hunt

Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, you may draw a card.

Pact of Negation

Counter target spell.
At the beginning of your next upkeep, pay {3}{U}{U}. If you don't, you lose the game.

Case of the Ransacked Lab

Instant and sorcery spells you cast cost {1} less to cast.
To solve — You've cast four or more instant and sorcery spells this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Whenever you cast an instant or sorcery spell, draw a card.

Wave Goodbye

Return each creature without a +1/+1 counter on it to its owner's hand.

Return to Nature

Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Exile target card from a graveyard.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Simic Guildgate

Simic Guildgate enters the battlefield tapped.
{T}: Add {G} or {U}.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Command Tower

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

Garruk's Uprising

When Garruk's Uprising enters the battlefield, if you control a creature with power 4 or greater, draw a card.
Creatures you control have trample. (They can deal excess combat damage to the player or planeswalker they're attacking.)
Whenever a creature with power 4 or greater enters the battlefield under your control, draw a card.

Arcane Signet

Elemental Bond

Whenever a creature with power 3 or greater enters the battlefield under your control, draw a card.

Hinterland Harbor

Hinterland Harbor enters the battlefield tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Overwhelming Stampede

Until end of turn, creatures you control gain trample and get +X/+X, where X is the greatest power among creatures you control.

Negate

Locket of Yesterdays

Spells you cast cost {1} less to cast for each card with the same name as that spell in your graveyard.

Emerald Medallion

Green spells you cast cost {1} less to cast.

Dreamroot Cascade

Dreamroot Cascade enters the battlefield tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Swan Song

Counter target enchantment, instant, or sorcery spell. Its controller creates a 2/2 blue Bird creature token with flying.

Kindred Discovery

As Kindred Discovery enters the battlefield, choose a creature type.
Whenever a creature you control of the chosen type enters the battlefield or attacks, draw a card.

Forest

Adrix and Nev, Twincasters

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
If one or more tokens would be created under your control, twice that many of those tokens are created instead.

Island

Slime Against Humanity

Create a 0/0 green Ooze creature token with trample. Put X +1/+1 counters on it, where X is two plus the total number of cards you own in exile and in your graveyard that are Oozes or are named Slime Against Humanity.
A deck can have any number of cards named Slime Against Humanity.