Jwari Shapeshifter

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

Talus Paladin

Whenever this creature or another Ally you control enters, you may have Allies you control gain lifelink until end of turn, and you may put a +1/+1 counter on this creature.

Gideon, Ally of Zendikar

+1: Until end of turn, Gideon 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."

Simic Signet

Kindred Dominance

Choose a creature type. Destroy all creatures that aren't of the chosen type.

Kor Bladewhirl

Rally — Whenever this creature or another Ally you control enters, creatures you control gain first strike until end of turn.

Katara, Water Tribe's Hope

Vigilance
When Katara enters, create a 1/1 white Ally creature token.
Waterbend {X}: Creatures you control have base power and toughness X/X until end of turn. X can't be 0. Activate only during your turn. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

General Tazri

When General Tazri enters, you may search your library for an Ally creature card, reveal it, put it into your hand, then shuffle.
{W}{U}{B}{R}{G}: Ally creatures you control get +X/+X until end of turn, where X is the number of colors among those creatures.

Arcane Adaptation

As this enchantment enters, choose a creature type.
Creatures you control are the chosen type in addition to their other types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.

Vantress Visions

Copy target activated or triggered ability you control. You may choose new targets for the copy.

Virtue of Knowledge

If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Virtue of Knowledge // Vantress Visions

Legion Loyalty

Creatures you control have myriad. (Whenever a creature with myriad attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)

Kindred Charge

Choose a creature type. For each creature you control of the chosen type, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Boros Signet

Harabaz Druid

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

Profane Tutor

Suspend 2—{1}{B} (Rather than cast this card from your hand, pay {1}{B} and exile it with two time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Search your library for a card, put that card into your hand, then shuffle.

Joraga Bard

Whenever this creature or another Ally you control enters, you may have Ally creatures you control gain vigilance until end of turn.

Sol Ring

Highland Berserker

Whenever this creature or another Ally you control enters, you may have Ally creatures you control gain first strike until end of turn.

Three Tree City

As Three Tree City enters, choose a creature type.
{T}: Add {C}.
{2}, {T}: Choose a color. Add an amount of mana of that color equal to the number of creatures you control of the chosen type.

Island

Plains

Reliquary Tower

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

Stoneforge Masterwork

Equipped creature gets +1/+1 for each other creature you control that shares a creature type with it.
Equip {2}

Venser, the Sojourner

+2: Exile target permanent you own. Return it to the battlefield under your control at the beginning of the next end step.
−1: Creatures can't be blocked this turn.
−8: You get an emblem with "Whenever you cast a spell, exile target permanent."

Counterspell

Mountain

Ondu Cleric

Whenever this creature or another Ally you control enters, you may gain life equal to the number of Allies you control.

Zada, Hedron Grinder

Whenever you cast an instant or sorcery spell that targets only Zada, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.

Murasa Pyromancer

Whenever this creature or another Ally you control enters, you may have this creature deal damage to target creature equal to the number of Allies you control.

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

Tajuru Archer

Whenever this creature or another Ally you control enters, you may have this creature deal damage to target creature with flying equal to the number of Allies you control.

Blade of Selves

Equipped creature has myriad. (Whenever it attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Equip {4}

Hero of Goma Fada

Rally — Whenever this creature or another Ally you control enters, creatures you control gain indestructible until end of turn.

Ally Encampment

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

Demonic Tutor

Search your library for a card, put that card into your hand, then shuffle.

Arcane Signet

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

Suki, Kyoshi Warrior

Suki's power is equal to the number of creatures you control.
Whenever Suki attacks, create a 1/1 white Ally creature token that's tapped and attacking.

Herald's Horn

As this artifact enters, choose a creature type.
Creature spells you cast of the chosen type cost {1} less to cast.
At the beginning of your upkeep, look at the top card of your library. If it's a creature card of the chosen type, you may reveal it and put it into your hand.

Cruel Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Captain's Claws

Equipped creature gets +1/+0.
Whenever equipped creature attacks, create a 1/1 white Kor Ally creature token that's tapped and attacking.
Equip {1}

Panharmonicon

If an artifact or creature entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Azorius Signet

Appa, Steadfast Guardian

Flash
Flying
When Appa enters, airbend any number of other target nonland permanents you control. (Exile them. While each one is exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever you cast a spell from exile, create a 1/1 white Ally creature token.

Roaming Throne

Ward {2}
As this creature enters, choose a creature type.
This creature is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Katara, the Fearless

If a triggered ability of an Ally you control triggers, that ability triggers an additional time.

Lantern Scout

Rally — Whenever this creature or another Ally you control enters, creatures you control gain lifelink until end of turn.

Sword of Wealth and Power

Equipped creature gets +2/+2 and has protection from instants and from sorceries.
Whenever equipped creature deals combat damage to a player, create a Treasure token. When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
Equip {2}

Kazandu Blademaster

First strike, vigilance
Whenever this creature or another Ally you control enters, you may put a +1/+1 counter on this creature.

Ondu Champion

Rally — Whenever this creature or another Ally you control enters, creatures you control gain trample until end of turn.

Kalastria Healer

Rally — Whenever this creature or another Ally you control enters, each opponent loses 1 life and you gain 1 life.

Retreat to Emeria

Landfall — Whenever a land you control enters, choose one —
• Create a 1/1 white Kor Ally creature token.
• Creatures you control get +1/+1 until end of turn.

Forest

Elesh Norn, Mother of Machines

Vigilance
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Permanents entering don't cause abilities of permanents your opponents control to trigger.

Vampiric Tutor

Kabira Evangel

Whenever this creature or another Ally you control enters, you may choose a color. If you do, Allies you control gain protection from the chosen color until end of turn.

Tazri, Beacon of Unity

This spell costs {1} less to cast for each creature in your party.
{2/U}{2/B}{2/R}{2/G}: Look at the top six cards of your library. You may reveal up to two Cleric, Rogue, Warrior, Wizard, and/or Ally cards from among them and put them into your hand. Put the rest on the bottom of your library in a random order.

Swamp

Tuktuk Scrapper

Whenever this creature or another Ally you control enters, you may destroy target artifact. If that artifact is put into a graveyard this way, this creature deals damage to that artifact's controller equal to the number of Allies you control.

Halimar Excavator

Whenever this creature or another Ally you control enters, target player mills X cards, where X is the number of Allies you control.

Yarok, the Desecrated

Deathtouch, lifelink
If a permanent entering causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Kazuul Warlord

Whenever this creature or another Ally you control enters, you may put a +1/+1 counter on each Ally creature you control.

Kor Entanglers

Rally — Whenever this creature or another Ally you control enters, tap target creature an opponent controls.

Distant Melody

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

Realmwalker

Changeling (This card is every creature type.)
As this creature enters, choose a creature type.
You may look at the top card of your library any time.
You may cast creature spells of the chosen type from the top of your library.

Angelic Captain

Flying
Whenever this creature attacks, it gets +1/+1 until end of turn for each other attacking Ally.

Hakoda, Selfless Commander

Vigilance
You may look at the top card of your library any time.
You may cast Ally spells from the top of your library.
Sacrifice Hakoda: Creatures you control get +0/+5 and gain indestructible until end of turn.

Mirror March

Whenever a nontoken creature you control enters, flip a coin until you lose a flip. For each flip you won, create a token that's a copy of that creature. Those tokens gain haste. Exile them at the beginning of the next end step.

Join the Ranks

Create two 1/1 white Soldier Ally creature tokens.

Oath of Gideon

When Oath of Gideon enters, create two 1/1 white Kor Ally creature tokens.
Each planeswalker you control enters with an additional loyalty counter on it.

Urza's Incubator

As this artifact enters, choose a creature type.
Creature spells of the chosen type cost {2} less to cast.

Makindi Patrol

Rally — Whenever this creature or another Ally you control enters, creatures you control gain vigilance until end of turn.

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.

Molten Echoes

As this enchantment enters, choose a creature type.
Whenever a nontoken creature you control of the chosen type enters, create a token that's a copy of that creature. That token gains haste. Exile it at the beginning of the next end step.

Gruul Signet

Patchwork Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

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.)

Hada Freeblade

Whenever this creature or another Ally you control enters, you may put a +1/+1 counter on this creature.