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.

Lantern Scout

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

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.

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.

Chasm Guide

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

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.

Ondu Cleric

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

Resolute Blademaster

Rally — Whenever this creature or another Ally you control enters, creatures you control gain double strike 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.

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.

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.

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.

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.

Harabaz Druid

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

Hero of Goma Fada

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

Beastcaller Savant

Haste
{T}: Add one mana of any color. Spend this mana only to cast a creature spell.

Tajuru Warcaller

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

Jwari Shapeshifter

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

Kazuul Warlord

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

Have

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.

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.

Sea Gate Loremaster

{T}: Draw a card for each Ally 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.