Makeshift Battalion

Battalion — Whenever Makeshift Battalion and at least two other creatures attack, put a +1/+1 counter on Makeshift Battalion.

Frontier Warmonger

Whenever one or more creatures attack one of your opponents or a planeswalker they control, those creatures gain menace until end of turn.

Captain of the Watch

Vigilance (Attacking doesn't cause this creature to tap.)
Other Soldier creatures you control get +1/+1 and have vigilance.
When Captain of the Watch enters, create three 1/1 white Soldier creature tokens.

Adriana, Captain of the Guard

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Other creatures you control have melee. (If a creature has multiple instances of melee, each triggers separately.)

Honored Crop-Captain

Whenever Honored Crop-Captain attacks, other attacking creatures get +1/+0 until end of turn.

Archangel of Thune

Flying
Lifelink (Damage dealt by this creature also causes you to gain that much life.)
Whenever you gain life, put a +1/+1 counter on each creature you control.

Linden, the Steadfast Queen

Vigilance (Attacking doesn't cause this creature to tap.)
Whenever a white creature you control attacks, you gain 1 life.

Consul's Lieutenant

First strike
Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
Whenever Consul's Lieutenant attacks, if it's renowned, other attacking creatures you control get +1/+1 until end of turn.

Syr Alin, the Lion's Claw

First strike (This creature deals combat damage before creatures without first strike.)
Whenever Syr Alin attacks, other creatures you control get +1/+1 until end of turn.

Perimeter Sergeant

Whenever Perimeter Sergeant attacks, other Humans you control get +1/+0 until end of turn.

Accorder Paladin

Battle cry (Whenever this creature attacks, each other attacking creature gets +1/+0 until end of turn.)

Blade Instructor

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

Victory's Envoy

At the beginning of your upkeep, put a +1/+1 counter on each other creature you control.

Tajic, Legion's Edge

Haste
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Prevent all noncombat damage that would be dealt to other creatures you control.
{R}{W}: Tajic, Legion's Edge gains first strike until end of turn.

Glorious Anthem

Preeminent Captain

First strike (This creature deals combat damage before creatures without first strike.)
Whenever Preeminent Captain attacks, you may put a Soldier creature card from your hand onto the battlefield tapped and attacking.

Molten Echoes

As Molten Echoes enters, choose a creature type.
Whenever a nontoken creature you control of the chosen type enters, create a token that's a copy of that creature. That token gains haste. Exile it at the beginning of the next end step.

Kytheon's Irregulars

Renown 1 (When this creature deals combat damage to a player, if it isn't renowned, put a +1/+1 counter on it and it becomes renowned.)
{W}{W}: Tap target creature.