Highland Berserker

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

Akoum Battlesinger

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

Sea Gate Loremaster

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

Kazuul Warlord

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

Talus Paladin

Whenever Talus Paladin 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 Talus Paladin.

Mountain

Join the Ranks

Create two 1/1 white Soldier Ally creature tokens.

Oran-Rief Survivalist

Whenever Oran-Rief Survivalist or another Ally you control enters, you may put a +1/+1 counter on Oran-Rief Survivalist.

Forest

Kazandu Blademaster

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

Exotic Orchard

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

Thriving Heath

Thriving Heath enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Harabaz Druid

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

Momentary Blink

Exile target creature you control, then return it to the battlefield under its owner's control.
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

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.

Arid Mesa

{T}, Pay 1 life, Sacrifice Arid Mesa: Search your library for a Mountain or Plains card, put it onto the battlefield, then shuffle.

Hada Freeblade

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

Ondu Cleric

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

Jwari Shapeshifter

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

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Cloudshift

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

Plains

Island

Volatile Fjord

({T}: Add {U} or {R}.)
Volatile Fjord enters tapped.

Kabira Evangel

Whenever Kabira Evangel 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.