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.

Makindi Patrol

Rally — Whenever Makindi Patrol or another Ally enters the battlefield under your control, creatures you control gain vigilance until end of turn.

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.

Allied Reinforcements

Create two 2/2 white Knight Ally creature tokens.

Jwari Shapeshifter

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

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.

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.

Kor Entanglers

Rally — Whenever Kor Entanglers or another Ally enters the battlefield under your control, tap target creature an opponent controls.

Kazuul Warlord

Whenever Kazuul Warlord or another Ally enters the battlefield under your control, you may put a +1/+1 counter on each Ally creature you control.

Lantern Scout

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

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.

Makindi Shieldmate

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

Join the Ranks

Create two 1/1 white Soldier Ally creature tokens.

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}

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.

Firemantle Mage

Rally — Whenever Firemantle Mage or another Ally enters the battlefield under your control, creatures you control gain menace until end of turn. (A creature with menace can't be blocked except by two or more creatures.)

Chasm Guide

Rally — Whenever Chasm Guide or another Ally enters the battlefield under your control, creatures you control gain haste until end of turn.

Highland Berserker

Whenever Highland Berserker or another Ally enters the battlefield under your control, you may have Ally creatures you control gain first strike until end of turn.

Joraga Bard

Whenever Joraga Bard or another Ally enters the battlefield under your control, you may have Ally creatures you control gain vigilance until end of turn.

Coat of Arms

Each creature gets +1/+1 for each other creature on the battlefield that shares at least one creature type with it. (For example, if two Goblin Warriors and a Goblin Shaman are on the battlefield, each gets +2/+2.)

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.

Kor Bladewhirl

Rally — Whenever Kor Bladewhirl or another Ally enters the battlefield under your control, creatures you control gain first strike until end of turn.

Unified Front

Converge — Create a 1/1 white Kor Ally creature token for each color of mana spent to cast this spell.

Akoum Battlesinger

Haste
Whenever Akoum Battlesinger or another Ally enters the battlefield under your control, you may have Ally creatures you control get +1/+0 until end of turn.

Angelic Captain

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

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.

General Tazri

When General Tazri enters the battlefield, 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.

Hada Freeblade

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