Ring of Valkas

Equipped creature has haste. (It can attack and {T} no matter when it came under your control.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's red.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Blade Historian

Attacking creatures you control have double strike.

Ring of Thune

Equipped creature has vigilance. (Attacking doesn't cause it to tap.)
At the beginning of your upkeep, put a +1/+1 counter on equipped creature if it's white.
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Boros Swiftblade

Hero's Blade

Equipped creature gets +3/+2.
Whenever a legendary creature you control enters, you may attach Hero's Blade to it.
Equip {4} ({4}: Attach to target creature you control. Equip only as a sorcery.)

Boros Signet

Boros Guildgate

This land enters tapped.
{T}: Add {R} or {W}.

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

Razia, Boros Archangel

Flying, vigilance, haste
{T}: The next 3 damage that would be dealt to target creature you control this turn is dealt to another target creature instead.

Plains

Unbreakable Formation

Creatures you control gain indestructible until end of turn.
Addendum — If you cast this spell during your main phase, put a +1/+1 counter on each of those creatures and they gain vigilance until end of turn.

Firemane Avenger

Flying
Battalion — Whenever Firemane Avenger and at least two other creatures attack, Firemane Avenger deals 3 damage to any target and you gain 3 life.

Sunhome, Fortress of the Legion

{T}: Add {C}.
{2}{R}{W}, {T}: Target creature gains double strike until end of turn.

Iroas, God of Victory

Indestructible
As long as your devotion to red and white is less than seven, Iroas isn't a creature.
Creatures you control have menace.
Prevent all damage that would be dealt to attacking creatures you control.

Light of the Legion

Flying
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
When Light of the Legion dies, put a +1/+1 counter on each white creature you control.

Kalemne, Disciple of Iroas

Double strike, vigilance
Whenever you cast a creature spell with mana value 5 or greater, you get an experience counter.
Kalemne, Disciple of Iroas gets +1/+1 for each experience counter you have.

Loxodon Warhammer

Equipped creature gets +3/+0 and has trample and lifelink.
Equip {3}

Relentless Assault

Untap all creatures that attacked this turn. After this main phase, there is an additional combat phase followed by an additional main phase.

Agrus Kos, Wojek Veteran

Whenever Agrus Kos, Wojek Veteran attacks, attacking red creatures get +2/+0 and attacking white creatures get +0/+2 until end of turn.

Stone Quarry

Stone Quarry enters tapped.
{T}: Add {R} or {W}.

Chance for Glory

Creatures you control gain indestructible. Take an extra turn after this one. At the beginning of that turn's end step, you lose the game.

Open the Armory

Search your library for an Aura or Equipment card, reveal it, put it into your hand, then shuffle.

Secluded Steppe

Secluded Steppe enters tapped.
{T}: Add {W}.
Cycling {W} ({W}, Discard this card: Draw a card.)

Anya, Merciless Angel

Flying
Anya, Merciless Angel gets +3/+3 for each opponent whose life total is less than half their starting life total.
As long as an opponent's life total is less than half their starting life total, Anya has indestructible.

Forgotten Cave

Forgotten Cave enters tapped.
{T}: Add {R}.
Cycling {R} ({R}, Discard this card: Draw a card.)

Mountain

Master Warcraft

Cast this spell only before attackers are declared.
You choose which creatures attack this turn.
You choose which creatures block this turn and how those creatures block.

Firemane Angel

Flying, first strike
At the beginning of your upkeep, if Firemane Angel is in your graveyard or on the battlefield, you may gain 1 life.
{6}{R}{R}{W}{W}: Return Firemane Angel from your graveyard to the battlefield. Activate only during your upkeep.

Aurelia, the Warleader

Flying, vigilance, haste
Whenever Aurelia attacks for the first time each turn, untap all creatures you control. After this phase, there is an additional combat phase.