Drana, Liberator of Malakir

Flying, first strike
Whenever Drana deals combat damage to a player, put a +1/+1 counter on each attacking creature you control.

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.

Zulaport Cutthroat

Whenever this creature or another creature you control dies, each opponent loses 1 life and you gain 1 life.

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.

Kalastria Healer

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

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.

Birds of Paradise

Kazandu Blademaster

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

Fellwar Stone

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

Makindi Patrol

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice this artifact: Draw a card.

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.

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.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Kor Bladewhirl

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

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.

Oran-Rief Survivalist

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

Panharmonicon

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

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

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 to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Munda, Ambush Leader

Haste
Rally — Whenever Munda or another Ally you control enters, you may look at the top four cards of your library. If you do, reveal any number of Ally cards from among them, then put those cards on top of your library in any order and the rest on the bottom in any order.

Urza's Incubator

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

Umara Raptor

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

Hada Freeblade

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Sea Gate Loremaster

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

Tajuru Warcaller

Rally — Whenever this creature or another Ally you control enters, creatures you control get +2/+2 until end of turn.

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}

Chromatic Lantern

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

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.

Rampant Growth

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

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.

Akoum Battlesinger

Haste
Whenever this creature or another Ally you control enters, you may have Ally creatures you control get +1/+0 until end of turn.

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."

Semester's End

Exile any number of target creatures and/or planeswalkers you control. At the beginning of the next end step, return each of them to the battlefield under its owner's control. Each of them enters with an additional +1/+1 counter on it if it's a creature and an additional loyalty counter on it if it's a planeswalker.

Conjurer's Closet

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.

Hagra Diabolist

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

Jwari Shapeshifter

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

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.

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.

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.

Veteran Warleader

Veteran Warleader's power and toughness are each equal to the number of creatures you control.
Tap another untapped Ally you control: This creature gains your choice of first strike, vigilance, or trample until end of turn.

Soulherder

Whenever a creature is exiled from the battlefield, put a +1/+1 counter on this creature.
At the beginning of your end step, you may exile another target creature you control, then return that card to the battlefield under its owner's control.

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.

Mina and Denn, Wildborn

You may play an additional land on each of your turns.
{R}{G}, Return a land you control to its owner's hand: Target creature gains trample until end of turn.

Katara, the Fearless

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

Ondu Champion

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

Hero of Goma Fada

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

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.

Mountain

Bojuka Brigand

This creature can't block.
Whenever this creature or another Ally you control enters, you may put a +1/+1 counter on this creature.

Unsettled Mariner

Changeling (This card is every creature type.)
Whenever you or a permanent you control becomes the target of a spell or ability an opponent controls, counter that spell or ability unless its controller pays {1}.

Ondu Cleric

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

Aang, Airbending Master

When Aang enters, airbend another target creature. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever one or more creatures you control leave the battlefield without dying, you get an experience counter.
At the beginning of your upkeep, create a 1/1 white Ally creature token for each experience counter you have.

Nahiri's Resolve

Creatures you control get +1/+0 and have haste.
At the beginning of your end step, exile any number of nontoken artifacts and/or creatures you control. Return those cards to the battlefield under their owner's control at the beginning of your next upkeep.

Ephemerate

Exile target creature you control, then return it to the battlefield under its owner's control.
Rebound (If you cast this spell from your hand, exile it as it resolves. At the beginning of your next upkeep, you may cast this card from exile without paying its mana cost.)

Harabaz Druid

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

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.

Arcane Signet

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

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.

Kodama's Reach

Angelic Captain

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

Door of Destinies

As this artifact enters, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on this artifact.
Creatures you control of the chosen type get +1/+1 for each charge counter on this artifact.