Akroan Hoplite

Whenever Akroan Hoplite attacks, it gets +X/+0 until end of turn, where X is the number of attacking creatures you control.

City on Fire

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
If a source you control would deal damage to a permanent or player, it deals triple that damage instead.

Sacred Peaks

({T}: Add {R} or {W}.)
Sacred Peaks enters tapped.

Valor in Akros

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

Battle Screech

Create two 1/1 white Bird creature tokens with flying.
Flashback—Tap three untapped white creatures you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Raise the Alarm

Create two 1/1 white Soldier creature tokens.

Boros Keyrune

{T}: Add {R} or {W}.
{R}{W}: Boros Keyrune becomes a 1/1 red and white Soldier artifact creature with double strike until end of turn. (It deals both first-strike and regular combat damage.)

Boros Signet

Resurgence

Creatures you control gain first strike and vigilance until end of turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Response

Response deals 5 damage to target attacking or blocking creature.

Response // Resurgence

Boros Guildgate

Boros Guildgate enters tapped.
{T}: Add {R} or {W}.

Leonin Warleader

Whenever Leonin Warleader attacks, create two 1/1 white Cat creature tokens with lifelink that are tapped and attacking.

Plains

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.

Train Troops

Create two 2/2 white Knight creature tokens with vigilance. (Then exile this card. You may cast the creature later from exile.)

Imodane's Recruiter

When Imodane's Recruiter enters, creatures you control get +1/+0 and gain haste until end of turn.

Imodane's Recruiter // Train Troops

Keldon Strike Team

Kicker {1}{W} (You may pay an additional {1}{W} as you cast this spell.)
When Keldon Strike Team enters, if it was kicked, create two 1/1 white Soldier creature tokens.
As long as Keldon Strike Team entered this turn, creatures you control have haste.

Dogpile

Dogpile deals damage to any target equal to the number of attacking creatures you control.

Cloudgoat Ranger

When Cloudgoat Ranger enters, create three 1/1 white Kithkin Soldier creature tokens.
Tap three untapped Kithkin you control: Cloudgoat Ranger gets +2/+0 and gains flying until end of turn.

Intangible Virtue

Creature tokens you control get +1/+1 and have vigilance.

Mountain

Assemble the Legion

At the beginning of your upkeep, put a muster counter on Assemble the Legion. Then create a 1/1 red and white Soldier creature token with haste for each muster counter on Assemble the Legion.