Plains

Piety Charm

Choose one —
• Destroy target Aura attached to a creature.
• Target Soldier creature gets +2/+2 until end of turn.
• Creatures you control gain vigilance until end of turn.

Unified Strike

Exile target attacking creature if its power is less than or equal to the number of Soldiers on the battlefield.

Frontline Strategist

Morph {W} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)
When Frontline Strategist is turned face up, prevent all combat damage non-Soldier creatures would deal this turn.

War Falcon

Flying
War Falcon can't attack unless you control a Knight or a Soldier.

Veteran Swordsmith

Other Soldier creatures you control get +1/+0.

Veteran Armorsmith

Other Soldier creatures you control get +0/+1.

Guardians' Pledge

White creatures you control get +2/+2 until end of turn.

Daru Stinger

Amplify 1 (As this creature enters the battlefield, put a +1/+1 counter on it for each Soldier card you reveal in your hand.)
{T}: Daru Stinger deals damage equal to the number of +1/+1 counters on it to target attacking or blocking creature.

Akrasan Squire

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)

Ancestral Blade

When Ancestral Blade enters the battlefield, create a 1/1 white Soldier creature token, then attach Ancestral Blade to it.
Equipped creature gets +1/+1.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Attended Knight

First strike
When Attended Knight enters the battlefield, create a 1/1 white Soldier creature token.