Getting

Sozin's Comet

Each creature you control gains firebending 5 until end of turn. (Whenever it attacks, add {R}{R}{R}{R}{R}. This mana lasts until end of combat.)
Foretell {2}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Bojuka Bog

This land enters tapped.
When this land enters, exile target player's graveyard.
{T}: Add {B}.

Fire Nation Palace

This land enters tapped unless you control a basic land.
{T}: Add {R}.
{1}{R}, {T}: Target creature you control gains firebending 4 until end of turn. (Whenever it attacks, add {R}{R}{R}{R}. This mana lasts until end of combat.)

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.

Sol Ring

Mystical Teachings

Search your library for an instant card or a card with flash, reveal it, put it into your hand, then shuffle.
Flashback {5}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Zuko, Seeking Honor

Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
Whenever you cast a noncreature spell, Zuko gains first strike until end of turn.
Whenever Zuko deals combat damage to a player, put a +1/+1 counter on him.

Silver Shroud Costume

Flash
When this Equipment enters, attach it to target creature you control. That creature gains shroud until end of turn. (It can't be the target of spells or abilities.)
Equipped creature can't be blocked.
Equip {3}

Stormcatch Mentor

Haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Instant and sorcery spells you cast cost {1} less to cast.

Have

Firebending Student

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Firebending X, where X is this creature's power. (Whenever this creature attacks, add X {R}. This mana lasts until end of combat.)

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice this land: You may cast spells this turn as though they had flash.

Watery Grave

({T}: Add {U} or {B}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Rakdos Signet

Leyline of Anticipation

If this card is in your opening hand, you may begin the game with it on the battlefield.
You may cast spells as though they had flash.

Counterspell

High Fae Trickster

Flash (You may cast this spell any time you could cast an instant.)
Flying
You may cast spells as though they had flash.

Ashling, Flame Dancer

You don't lose unspent red mana as steps and phases end.
Magecraft — Whenever you cast or copy an instant or sorcery spell, discard a card, then draw a card. If this is the second time this ability has resolved this turn, Ashling deals 2 damage to each opponent and each creature they control. If it's the third time, add {R}{R}{R}{R}.

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Amphibian Downpour

Flash
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies. Copies become tokens.)
Enchant creature
Enchanted creature loses all abilities and is a blue Frog creature with base power and toughness 1/1.

Dimir Signet

Etali, Primal Storm

Whenever Etali attacks, exile the top card of each player's library, then you may cast any number of spells from among those cards without paying their mana costs.

Iroh, Dragon of the West

Haste
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
At the beginning of combat on your turn, each creature you control with a counter on it gains firebending 2 until end of turn. (Whenever it attacks, add {R}{R}. This mana lasts until end of combat.)

Kess, Dissident Mage

Flying
Once during each of your turns, you may cast an instant or sorcery spell from your graveyard. If a spell cast this way would be put into your graveyard, exile it instead.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Electrodominance

Electrodominance deals X damage to any target. You may cast a spell with mana value X or less from your hand without paying its mana cost.

Azula, On the Hunt

Firebending 2 (Whenever this creature attacks, add {R}{R}. This mana lasts until end of combat.)
Whenever Azula attacks, you lose 1 life and create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Avatar Roku

Firebending 4 (Whenever this creature attacks, add {R}{R}{R}{R}. This mana lasts until end of combat.)
{8}: Create a 4/4 red Dragon creature token with flying and firebending 4.

The Legend of Roku

(As this Saga enters and after your draw step, add a lore counter.)
I — Exile the top three cards of your library. Until the end of your next turn, you may play those cards.
II — Add one mana of any color.
III — Exile this Saga, then return it to the battlefield transformed under your control.

The Legend of Roku // Avatar Roku

Command Tower

{T}: Add one mana of any color in your commander's color identity.

Ozai, the Phoenix King

Trample, firebending 4, haste
If you would lose unspent mana, that mana becomes red instead.
Ozai has flying and indestructible as long as you have six or more unspent mana.

Leyline Tyrant

Flying
You don't lose unspent red mana as steps and phases end.
When this creature dies, you may pay any amount of {R}. When you do, it deals that much damage to any target.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

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.)

Azula, Cunning Usurper

Firebending 2 (Whenever this creature attacks, add {R}{R}. This mana lasts until end of combat.)
When Azula enters, target opponent exiles a nontoken creature they control, then they exile a nonland card from their graveyard.
During your turn, you may cast cards exiled with Azula and you may cast them as though they had flash. Mana of any type can be spent to cast those spells.

Guttersnipe

Whenever you cast an instant or sorcery spell, this creature deals 2 damage to each opponent.

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

Professor Onyx

Magecraft — Whenever you cast or copy an instant or sorcery spell, each opponent loses 2 life and you gain 2 life.
+1: You lose 1 life. Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
−3: Each opponent sacrifices a creature with the greatest power among creatures that player controls.
−8: Each opponent may discard a card. If they don't, they lose 3 life. Repeat this process six more times.

Vindictive Warden

Menace (This creature can't be blocked except by two or more creatures.)
Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
{3}: This creature deals 1 damage to each opponent.

Twin Blades

Flash
When this Equipment enters, attach it to target creature you control. That creature gains double strike until end of turn.
Equipped creature gets +1/+1.
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Notion Thief

Flash
If an opponent would draw a card except the first one they draw in each of their draw steps, instead that player skips that draw and you draw a card.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Bender's Waterskin

Untap this artifact during each other player's untap step.
{T}: Add one mana of any color.

Zuko, Firebending Master

First strike
Firebending X, where X is the number of experience counters you have. (Whenever this creature attacks, add X {R}. This mana lasts until end of combat.)
Whenever you cast a spell during combat, you get an experience counter.

Purphoros, God of the Forge

Indestructible
As long as your devotion to red is less than five, Purphoros isn't a creature.
Whenever another creature you control enters, Purphoros deals 2 damage to each opponent.
{2}{R}: Creatures you control get +1/+0 until end of turn.

Fire Nation Turret

At the beginning of combat on your turn, up to one target creature gets +2/+0 and gains firebending 2 until end of turn.
{R}: Put a charge counter on this artifact.
Remove fifty charge counters from this artifact: It deals 50 damage to any target.

Veyran, Voice of Duality

Magecraft — Whenever you cast or copy an instant or sorcery spell, Veyran gets +1/+1 until end of turn.
If you casting or copying an instant or sorcery spell causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Whispersilk Cloak

Equipped creature can't be blocked and has shroud. (It can't be the target of spells or abilities.)
Equip {2}

Temple of Malice

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {B} or {R}.

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Storm-Kiln Artist

This creature gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Reverberate

Copy target instant or sorcery spell. You may choose new targets for the copy.

Archmage of Runes

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, draw a card.

Crackle with Power

Crackle with Power deals five times X damage to each of up to X targets.

Mountain

Arcane Signet

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Past in Flames

Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Unleash Fury

Double the power of target creature until end of turn.

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

The Last Agni Kai

Target creature you control fights target creature an opponent controls. If the creature the opponent controls is dealt excess damage this way, add that much {R}.
Until end of turn, you don't lose unspent red mana as steps and phases end.

Realm of Koh

This land enters tapped unless you control a basic land.
{T}: Add {B}.
{3}{B}, {T}: Create a 1/1 colorless Spirit creature token with "This token can't block or be blocked by non-Spirit creatures."

Run Amok

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

Firebender Ascension

When this enchantment enters, create a 2/2 red Soldier creature token with firebending 1.
Whenever a creature you control attacking causes a triggered ability of that creature to trigger, put a quest counter on this enchantment. Then if it has four or more quest counters on it, you may copy that ability. You may choose new targets for the copy.

Full Throttle

After this main phase, there are two additional combat phases.
At the beginning of each combat this turn, untap all creatures that attacked this turn.

Great Train Heist

Spree (Choose one or more additional costs.)
+ {2}{R} — Untap all creatures you control. If it's your combat phase, there is an additional combat phase after this phase.
+ {2} — Creatures you control get +1/+0 and gain first strike until end of turn.
+ {R} — Choose target opponent. Whenever a creature you control deals combat damage to that player this turn, create a tapped Treasure token.

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.

Sedgemoor Witch

Menace
Ward—Pay 3 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 3 life.)
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a 1/1 black and green Pest creature token with "When this token dies, you gain 1 life."

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.

Izzet Signet

Twinning Staff

If you would copy a spell one or more times, instead copy it that many times plus an additional time. You may choose new targets for the additional copy.
{7}, {T}: Copy target instant or sorcery spell you control. You may choose new targets for the copy.

Thousand-Year Storm

Whenever you cast an instant or sorcery spell, copy it for each other instant and sorcery spell you've cast before it this turn. You may choose new targets for the copies.

Temple of Deceit

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {B}.

Crumbling Necropolis

This land enters tapped.
{T}: Add {U}, {B}, or {R}.

Island

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Swamp

Temple of Epiphany

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {R}.

Fire Lord Azula

Firebending 2 (Whenever this creature attacks, add {R}{R}. This mana lasts until end of combat.)
Whenever you cast a spell while Fire Lord Azula is attacking, copy that spell. You may choose new targets for the copy. (A copy of a permanent spell becomes a token.)

Hullbreaker Horror

Flash
This spell can't be countered.
Whenever you cast a spell, choose up to one —
• Return target spell you don't control to its owner's hand.
• Return target nonland permanent to its owner's hand.

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Lightning Strike

Lightning Strike deals 3 damage to any target.

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.

Ran and Shaw

Flying, firebending 2
When Ran and Shaw enter, if you cast them and there are three or more Dragon and/or Lesson cards in your graveyard, create a token that's a copy of Ran and Shaw, except it's not legendary.
{3}{R}: Dragons you control get +2/+0 until end of turn.

Electro, Assaulting Battery

Flying
You don't lose unspent red mana as steps and phases end.
Whenever you cast an instant or sorcery spell, add {R}.
When Electro leaves the battlefield, you may pay {X}. When you do, he deals X damage to target player.

Lo and Li, Twin Tutors

When Lo and Li enter, search your library for a Lesson or Noble card, reveal it, put it into your hand, then shuffle.
Noble creatures you control and Lesson spells you control have lifelink.