Hada Freeblade

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

Nomad Outpost

Nomad Outpost enters tapped.
{T}: Add {R}, {W}, or {B}.

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.

Kazandu Blademaster

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

Jwari Shapeshifter

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

Panharmonicon

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

Halimar Excavator

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

Harabaz Druid

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

Mystic Monastery

Mystic Monastery enters tapped.
{T}: Add {U}, {R}, or {W}.

Ondu Cleric

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

Karn's Bastion

{T}: Add {C}.
{4}, {T}: Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

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.