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.

Cathars' Crusade

Whenever a creature enters the battlefield under your control, put a +1/+1 counter on each creature you control.

Ally Encampment

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast an Ally spell.
{1}, {T}, Sacrifice Ally Encampment: Return target Ally you control to its owner's hand.

Hada Freeblade

Whenever Hada Freeblade or another Ally enters the battlefield under your control, you may put a +1/+1 counter on Hada Freeblade.

Bojuka Brigand

Bojuka Brigand can't block.
Whenever Bojuka Brigand or another Ally enters the battlefield under your control, you may put a +1/+1 counter on Bojuka Brigand.

Munda's Vanguard

Cohort — {T}, Tap an untapped Ally you control: Put a +1/+1 counter on each creature you control.

Eerie Interlude

Exile any number of target creatures you control. Return those cards to the battlefield under their owner's control at the beginning of the next end step.

Lantern Scout

Rally — Whenever Lantern Scout or another Ally enters the battlefield under your control, creatures you control gain lifelink until end of turn.

Halimar Excavator

Whenever Halimar Excavator or another Ally enters the battlefield under your control, target player mills X cards, where X is the number of Allies you control.

Rite of Replication

Kicker {5} (You may pay an additional {5} as you cast this spell.)
Create a token that's a copy of target creature. If this spell was kicked, create five of those tokens instead.

Sol Ring

Talus Paladin

Whenever Talus Paladin or another Ally enters the battlefield under your control, you may have Allies you control gain lifelink until end of turn, and you may put a +1/+1 counter on Talus Paladin.

Agadeem Occultist

{T}: Put target creature card from an opponent's graveyard onto the battlefield under your control if its mana value is less than or equal to the number of Allies you control.

Serene Steward

Whenever you gain life, you may pay {W}. If you do, put a +1/+1 counter on target creature.

Patriarch's Bidding

Each player chooses a creature type. Each player returns all creature cards of a type chosen this way from their graveyard to the battlefield.

Hero of Goma Fada

Rally — Whenever Hero of Goma Fada or another Ally enters the battlefield under your control, creatures you control gain indestructible until end of turn.

Arcane Signet

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

Kazandu Blademaster

First strike, vigilance
Whenever Kazandu Blademaster or another Ally enters the battlefield under your control, you may put a +1/+1 counter on Kazandu Blademaster.

Sea Gate Loremaster

{T}: Draw a card for each Ally you control.

Harabaz Druid

{T}: Add X mana of any one color, where X is the number of Allies you control.

March from the Tomb

Return any number of target Ally creature cards with total mana value 8 or less from your graveyard to the battlefield.

Astral Cornucopia

Astral Cornucopia enters the battlefield with X charge counters on it.
{T}: Choose a color. Add one mana of that color for each charge counter on Astral Cornucopia.

Gideon, Ally of Zendikar

+1: Until end of turn, Gideon, Ally of Zendikar becomes a 5/5 Human Soldier Ally creature with indestructible that's still a planeswalker. Prevent all damage that would be dealt to him this turn.
0: Create a 2/2 white Knight Ally creature token.
−4: You get an emblem with "Creatures you control get +1/+1."

Kabira Evangel

Whenever Kabira Evangel or another Ally enters the battlefield under your control, you may choose a color. If you do, Allies you control gain protection from the chosen color until end of turn.

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

Turntimber Ranger

Whenever Turntimber Ranger or another Ally enters the battlefield under your control, you may create a 2/2 green Wolf creature token. If you do, put a +1/+1 counter on Turntimber Ranger.

Bala Ged Thief

Whenever Bala Ged Thief or another Ally enters the battlefield under your control, target player reveals a number of cards from their hand equal to the number of Allies you control. You choose one of them. That player discards that card.

Mountain

Ondu Cleric

Whenever Ondu Cleric or another Ally enters the battlefield under your control, you may gain life equal to the number of Allies you control.

Command Tower

Reflections of Littjara

As Reflections of Littjara enters the battlefield, 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.)

Teleportation Circle

At the beginning of your end step, exile up to one target artifact or creature you control, then return that card to the battlefield under its owner's control.

Golden Argosy

Whenever Golden Argosy attacks, exile each creature that crewed it this turn. Return them to the battlefield tapped under their owner's control at the beginning of the next end step.
Crew 1 (Tap any number of creatures you control with total power 1 or more: This Vehicle becomes an artifact creature until end of turn.)

Cover of Darkness

As Cover of Darkness enters the battlefield, choose a creature type.
Creatures of the chosen type have fear. (They can't be blocked except by artifact creatures and/or black creatures.)

Seascape Aerialist

Whenever Seascape Aerialist or another Ally enters the battlefield under your control, you may have Ally creatures you control gain flying until end of turn.

Hagra Diabolist

Whenever Hagra Diabolist or another Ally enters the battlefield under your control, you may have target player lose life equal to the number of Allies you control.

Kalastria Healer

Rally — Whenever Kalastria Healer or another Ally enters the battlefield under your control, each opponent loses 1 life and you gain 1 life.

Drana's Emissary

Flying
At the beginning of your upkeep, each opponent loses 1 life and you gain 1 life.

Exotic Orchard

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

Jwari Shapeshifter

You may have Jwari Shapeshifter enter the battlefield as a copy of any Ally creature on the battlefield.

Aetherize

Return all attacking creatures to their owner's hand.

Atraxa, Praetors' Voice

Flying, vigilance, deathtouch, lifelink
At the beginning of your end step, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Vivid Creek

Vivid Creek enters the battlefield tapped with two charge counters on it.
{T}: Add {U}.
{T}, Remove a charge counter from Vivid Creek: Add one mana of any color.