Harbin, Vanguard Aviator

Flying
Whenever you attack with five or more Soldiers, creatures you control get +1/+1 and gain flying until end of turn.

Yotian Frontliner

Whenever Yotian Frontliner attacks, another target creature you control gets +1/+1 until end of turn.
Unearth {W} ({W}: Return this card from your graveyard to the battlefield. It gains haste. Exile it at the beginning of the next end step or if it would leave the battlefield. Unearth only as a sorcery.)

Recruitment Officer

{3}{W}: Look at the top four cards of your library. You may reveal a creature card with mana value 3 or less from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Warden of the Inner Sky

As long as Warden of the Inner Sky has three or more counters on it, it has flying and vigilance.
Tap three untapped artifacts and/or creatures you control: Put a +1/+1 counter on Warden of the Inner Sky. Scry 1. Activate only as a sorcery.

Case of the Gateway Express

When this Case enters, choose target creature you don't control. Each creature you control deals 1 damage to that creature.
To solve — Three or more creatures attacked this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Creatures you control get +1/+0.

Resolute Reinforcements

Flash
When Resolute Reinforcements enters, create a 1/1 white Soldier creature token.

Valiant Veteran

Other Soldiers you control get +1/+1.
{3}{W}{W}, Exile Valiant Veteran from your graveyard: Put a +1/+1 counter on each Soldier you control.

Protect the Negotiators

Kicker {W} (You may pay an additional {W} as you cast this spell.)
If this spell was kicked, create a 1/1 white Soldier creature token.
Counter target spell unless its controller pays {1} for each creature you control.

Zephyr Sentinel

Flash
Flying
When Zephyr Sentinel enters, return up to one other target creature you control to its owner's hand. If it was a Soldier, put a +1/+1 counter on Zephyr Sentinel.

Siege Veteran

At the beginning of combat on your turn, put a +1/+1 counter on target creature you control.
Whenever another nontoken Soldier you control dies, create a 1/1 colorless Soldier artifact creature token.

Skystrike Officer

Flying
Whenever Skystrike Officer attacks, create a 1/1 colorless Soldier artifact creature token.
Tap three untapped Soldiers you control: Draw a card.

Myrel, Shield of Argive

During your turn, your opponents can't cast spells or activate abilities of artifacts, creatures, or enchantments.
Whenever Myrel, Shield of Argive attacks, create X 1/1 colorless Soldier artifact creature tokens, where X is the number of Soldiers you control.

Snow-Covered Plains

Snow-Covered Island

Adarkar Wastes

{T}: Add {C}.
{T}: Add {W} or {U}. Adarkar Wastes deals 1 damage to you.

Fortified Beachhead

As Fortified Beachhead enters, you may reveal a Soldier card from your hand. Fortified Beachhead enters tapped unless you revealed a Soldier card this way or you control a Soldier.
{T}: Add {W} or {U}.
{5}, {T}: Soldiers you control get +1/+1 until end of turn.

Seachrome Coast

Seachrome Coast enters tapped unless you control two or fewer other lands.
{T}: Add {W} or {U}.

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.