Valor in Akros

Whenever a creature you control enters, creatures you control get +1/+1 until end of turn.

Erkenbrand, Lord of Westfold

Whenever Erkenbrand, Lord of Westfold or another Human you control enters, creatures you control get +1/+0 until end of turn.

Kazuul Warlord

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

Kazandu Blademaster

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

Hada Freeblade

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

Goldnight Commander

Whenever another creature you control enters, creatures you control get +1/+1 until end of turn.

Harabaz Druid

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

Shared Animosity

Whenever a creature you control attacks, it gets +1/+0 until end of turn for each other attacking creature that shares a creature type with it.

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Beregond of the Guard

Whenever Beregond of the Guard or another Human you control enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Tajuru Beastmaster

Rally — Whenever Tajuru Beastmaster or another Ally you control enters, creatures you control get +1/+1 until end of turn.

Tana, the Bloodsower

Trample
Whenever Tana, the Bloodsower deals combat damage to a player, create that many 1/1 green Saproling creature tokens.
Partner (You can have two commanders if both have partner.)

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.

Livio, Oathsworn Sentinel

{1}{W}: Choose another target creature. Its controller may exile it with an aegis counter on it.
{2}{W}, {T}: Return all exiled cards with aegis counters on them to the battlefield under their owners' control.
Partner (You can have two commanders if both have partner.)

Oran-Rief Survivalist

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

Ondu War Cleric

Cohort — {T}, Tap an untapped Ally you control: You gain 2 life.

Expedition Envoy

Reckless Cohort

Reckless Cohort attacks each combat if able unless you control another Ally.

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.

Kyler, Sigardian Emissary

Whenever another Human you control enters, put a +1/+1 counter on Kyler, Sigardian Emissary.
Other Humans you control get +1/+1 for each counter on Kyler.

Call for Unity

Revolt — At the beginning of your end step, if a permanent you controlled left the battlefield this turn, put a unity counter on Call for Unity.
Creatures you control get +1/+1 for each unity counter on Call for Unity.

Tajuru Warcaller

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