How to Start a Riot

Target creature gains menace until end of turn. (It can't be blocked except by two or more creatures.)
Creatures target player controls get +2/+0 until end of turn.

Iroh, Firebending Instructor

Whenever Iroh attacks, attacking creatures get +1/+1 until end of turn.

Fire Nation's Conquest

Fated Firepower

Flash
This enchantment enters with X fire counters on it.
If a source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus an amount of damage equal to the number of fire counters on this enchantment instead.

Loyal Fire Sage

Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
{5}: Create a 1/1 white Ally creature token.

Run Amok

Target attacking creature gets +3/+3 and gains trample until end of turn.

Zuko, Exiled Prince

Firebending 3 (Whenever this creature attacks, add {R}{R}{R}. This mana lasts until end of combat.)
{3}: Exile the top card of your library. You may play that card this turn.

Deserter's Disciple

{T}: Another target creature you control with power 2 or less can't be blocked this turn.

Explosive Shot

Explosive Shot deals 4 damage to target creature.

Zuko, Avatar Hunter

Reach (This creature can block creatures with flying.)
Whenever you cast a red spell, create a 2/2 red Soldier creature token.

Fire Sages

Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
{1}{R}{R}: Put a +1/+1 counter on this creature.

Zhao, the Seething Flame

Menace (This creature can't be blocked except by two or more creatures.)

Rough Rhino Cavalry

Firebending 2 (Whenever this creature attacks, add {R}{R}. This mana lasts until end of combat.)
Exhaust — {8}: Put two +1/+1 counters on this creature. It gains trample until end of turn. (Activate each exhaust ability only once.)

Mountain

Fire Nation Attacks

Create two 2/2 red Soldier creature tokens with firebending 1. (Whenever a creature with firebending 1 attacks, add {R}. This mana lasts until end of combat.)
Flashback {8}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Redirect Lightning

As an additional cost to cast this spell, pay 5 life or pay {2}.
Change the target of target spell or ability with a single target.

Lightning Strike

Lightning Strike deals 3 damage to any target.

Fire Nation Archers

Reach (This creature can block creatures with flying.)
{5}: This creature deals 2 damage to each opponent. Create a 2/2 red Soldier creature token.

Komodo Rhino

Trample (This creature can deal excess combat damage to the player it's attacking.)