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.

Haunted Ridge

This land enters tapped unless you control two or more other lands.
{T}: Add {B} or {R}.

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.

Harnfel, Horn of Bounty

Discard a card: Exile the top two cards of your library. You may play those cards this turn.

Birgi, God of Storytelling

Whenever you cast a spell, add {R}. Until end of turn, you don't lose this mana as steps and phases end.
Creatures you control can boast twice during each of your turns rather than once.

Birgi, God of Storytelling // Harnfel, Horn of Bounty

Mountain

Battle Hymn

Bender's Waterskin

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

Strionic Resonator

{2}, {T}: Copy target triggered ability you control. You may choose new targets for the copy. (A triggered ability uses the words "when," "whenever," or "at.")

Doubling Cube

{3}, {T}: Double the amount of each type of unspent mana you have.

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.

Blazemire Verge

{T}: Add {B}.
{T}: Add {R}. Activate only if you control a Swamp or a Mountain.

Bubbling Muck

Until end of turn, whenever a player taps a Swamp for mana, that player adds an additional {B}.

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

Zhao, Ruthless Admiral

Firebending 2 (Whenever this creature attacks, add {R}{R}. This mana lasts until end of combat.)
Whenever you sacrifice another permanent, creatures you control get +1/+0 until end of turn.

Blaze

Horizon Stone

If you would lose unspent mana, that mana becomes colorless instead.

Irencrag Feat

Add seven {R}. You can cast only one more spell this turn.

Avatar Roku, Firebender

Whenever a player attacks, add six {R}. Until end of combat, you don't lose this mana as steps end.
{R}{R}{R}: Target creature gets +3/+0 until end of turn.

Dragonrage

Add {R} for each attacking creature you control. Until end of turn, attacking creatures you control gain "{R}: This creature gets +1/+0 until end of turn."

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.

Cabal Coffers

{2}, {T}: Add {B} for each Swamp you control.

The Eternity Elevator

{T}: Add {C}{C}{C}.
Station (Tap another creature you control: Put charge counters equal to its power on this Spacecraft. Station only as a sorcery.)
STATION 20+
{T}: Add X mana of any one color, where X is the number of charge counters on The Eternity Elevator.

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.

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.

Fire Lord Sozin

Menace, firebending 3 (Whenever this creature attacks, add {R}{R}{R}. This mana lasts until end of combat.)
Whenever Fire Lord Sozin deals combat damage to a player, you may pay {X}. When you do, put any number of target creature cards with total mana value X or less from that player's graveyard onto the battlefield under your control.

The Rise of Sozin

(As this Saga enters and after your draw step, add a lore counter.)
I — Destroy all creatures.
II — Choose a card name. Search target opponent's graveyard, hand, and library for up to four cards with that name and exile them. Then that player shuffles.
III — Exile this Saga, then return it to the battlefield transformed under your control.

The Rise of Sozin // Fire Lord Sozin

Peter Parker's Camera

This artifact enters with three film counters on it.
{2}, {T}, Remove a film counter from this artifact: Copy target activated or triggered ability you control. You may choose new targets for the copy.

Sol Ring

Fire Nation Occupation

When this enchantment enters, create a 2/2 red Soldier creature token with firebending 1. (Whenever it attacks, add {R}. This mana lasts until end of combat.)
Whenever you cast a spell during an opponent's turn, create a 2/2 red Soldier creature token with firebending 1.

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.)

Dragonskull Summit

This land enters tapped unless you control a Swamp or a Mountain.
{T}: Add {B} or {R}.

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.

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.

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Iron Myr

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.

The Peregrine Dynamo

Haste
{1}, {T}: Copy target activated or triggered ability you control from another legendary source that's not a commander. You may choose new targets for the copy. (Mana abilities can't be targeted.)

Songs of the Damned

Add {B} for each creature card in your graveyard.

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.")

Pyretic Ritual

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.

Tainted Peak

{T}: Add {C}.
{T}: Add {B} or {R}. Activate only if you control a Swamp.

Charcoal Diamond

This artifact enters tapped.
{T}: Add {B}.

Devil's Play

Devil's Play deals X damage to any target.
Flashback {X}{R}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Brazen Collector

First strike
Whenever this creature attacks, add {R}. Until end of turn, you don't lose this mana as steps and phases end.

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.

Endrider Catalyzer

Start your engines! (If you have no speed, it starts at 1. It increases once on each of your turns when an opponent loses life. Max speed is 4.)
Max speed — {T}: Add {R}{R}.

Geothermal Bog

({T}: Add {B} or {R}.)
This land enters tapped.

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Seething Song

Banefire

Banefire deals X damage to any target.
If X is 5 or more, this spell can't be countered and the damage can't be prevented.

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.

Canyon Slough

({T}: Add {B} or {R}.)
This land enters tapped.
Cycling {2} ({2}, Discard this card: Draw a card.)

Cruel Administrator

Raid — This creature enters with a +1/+1 counter on it if you attacked this turn.
Whenever this creature attacks, create a 2/2 red Soldier creature token with firebending 1. (Whenever it attacks, add {R}. This mana lasts until end of combat.)

Geosurge

Add {R}{R}{R}{R}{R}{R}{R}. Spend this mana only to cast artifact or creature spells.

Braid of Fire

Cumulative upkeep—Add {R}. (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

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.)

Akoum Refuge

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {B} or {R}.

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.)

Raucous Theater

({T}: Add {B} or {R}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Smoldering Marsh

({T}: Add {B} or {R}.)
This land enters tapped unless you control two or more basic lands.

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.)

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.

Deadly Dancer

Trample
When this creature transforms into Deadly Dancer, add {R}{R}. Until end of turn, you don't lose this mana as steps and phases end.
{R}{R}: This creature and another target creature each get +1/+0 until end of turn.

Alluring Suitor

When you attack with exactly two creatures, transform this creature.

Alluring Suitor // Deadly Dancer

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.

Foreboding Ruins

As this land enters, you may reveal a Swamp or Mountain card from your hand. If you don't, this land enters tapped.
{T}: Add {B} or {R}.

Dark Ritual

Neheb, Dreadhorde Champion

Trample
Whenever Neheb deals combat damage to a player or planeswalker, you may discard any number of cards. If you do, draw that many cards and add that much {R}. Until end of turn, you don't lose this mana as steps and phases end.

Sulfurous Mire

Fall of the Titans

Surge {X}{R} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Fall of the Titans deals X damage to each of up to two targets.

Fire Diamond

This artifact enters tapped.
{T}: Add {R}.

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}.

Volcanic Geyser

Volcanic Geyser deals X damage to any target.

Swamp

Blood Crypt

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

Mana Geyser

Add {R} for each tapped land your opponents control.

Infernal Plunge

As an additional cost to cast this spell, sacrifice a creature.
Add {R}{R}{R}.

Return the Favor

Spree (Choose one or more additional costs.)
+ {1} — Copy target instant spell, sorcery spell, activated ability, or triggered ability. You may choose new targets for the copy.
+ {1} — Change the target of target spell or ability with a single target.

Rousing Refrain

Add {R} for each card in target opponent's hand. Until end of turn, you don't lose this mana as steps and phases end. Exile Rousing Refrain with three time counters on it.
Suspend 3—{1}{R} (Rather than cast this card from your hand, you may pay {1}{R} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)