Have

Lightning Strike

Lightning Strike deals 3 damage to any target.

Smoldering Marsh

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

Thought Vessel

You have no maximum hand size.
{T}: Add {C}.

Eroded Canyon

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {U} or {R}.

Arcane Bombardment

Whenever you cast your first instant or sorcery spell each turn, exile an instant or sorcery card at random from your graveyard. Then copy each card exiled with this enchantment. You may cast any number of the copies without paying their mana costs.

Getting

Lightning Greaves

Equipped creature has haste and shroud. (It can't be the target of spells or abilities.)
Equip {0}

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.

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.

Free from Flesh

Target creature gets +2/+2 until end of turn. Put two oil counters on it.

Maestros Theater

When this land enters, sacrifice it. When you do, search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

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.

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.

Heartless Act

Choose one —
• Destroy target creature with no counters on it.
• Remove up to three counters from target creature.

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Counterspell

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.)

Sol Ring

Evolving Wilds

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Combustion Technique

Combustion Technique deals damage equal to 2 plus the number of Lesson cards in your graveyard to target creature. If that creature would die this turn, exile it instead.

Soured Springs

This land enters tapped.
When this land enters, it deals 1 damage to target opponent.
{T}: Add {U} or {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.)

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.

Gloomlake Verge

{T}: Add {U}.
{T}: Add {B}. Activate only if you control an Island or a Swamp.

Zada, Hedron Grinder

Whenever you cast an instant or sorcery spell that targets only Zada, copy that spell for each other creature you control that the spell could target. Each copy targets a different one of those creatures.

Don't Have

Faerie Mastermind

Flash
Flying
Whenever an opponent draws their second card each turn, you draw a card.
{3}{U}: Each player draws a card.

Unexpected Windfall

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Rite of the Dragoncaller

Whenever you cast an instant or sorcery spell, create a 5/5 red Dragon creature token with flying.

Wastes

Crackle with Power

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

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.

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.

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.

Blazing Crescendo

Target creature gets +3/+1 until end of turn.
Exile the top card of your library. Until the end of your next turn, you may play that card.

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.)

Unleash Fury

Double the power of target creature until end of turn.

Increasing Vengeance

Copy target instant or sorcery spell you control. If this spell was cast from a graveyard, copy that spell twice instead. You may choose new targets for the copies.
Flashback {3}{R}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Seething Song

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.

Terminate

Destroy target creature. It can't be regenerated.

Quicken

The next sorcery spell you cast this turn can be cast as though it had flash. (It can be cast any time you could cast an instant.)
Draw a card.

The Endstone

Whenever you play a land or cast a spell, draw a card.
At the beginning of your end step, your life total becomes half your starting life total, rounded up.

Shore Up

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Seething Landscape

{T}: Add {C}.
{T}, Sacrifice this land: Search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.
Cycling {U}{B}{R} ({U}{B}{R}, Discard this card: Draw a card.)

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. This artifact deals 1 damage to you.

Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

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.

Cabal Ritual

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

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}

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.

Cunning Maneuver

Target creature gets +3/+1 until end of turn.
Create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Azula Always Lies

Choose one or both —
• Target creature gets -1/-1 until end of turn.
• Put a +1/+1 counter on target creature.

Valley Floodcaller

Flash
You may cast noncreature spells as though they had flash.
Whenever you cast a noncreature spell, Birds, Frogs, Otters, and Rats you control get +1/+1 until end of turn. Untap them.

Frantic Search

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

Arcane Signet

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

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Enter the Enigma

Target creature can't be blocked this turn.
Draw a card.

Bender's Waterskin

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

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.

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.

Firebending Lesson

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Firebending Lesson deals 2 damage to target creature. If this spell was kicked, it deals 5 damage to that creature instead.

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.)

Thrill of Possibility

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

Snap

Return target creature to its owner's hand. Untap up to two lands.

Dark Ritual

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.

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.)

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.

Fierce Guardianship

If you control a commander, you may cast this spell without paying its mana cost.
Counter target noncreature spell.

Overkill

Target creature gets -0/-9999 until end of turn.

Murder

Full Bore

Target creature you control gets +3/+2 until end of turn. If that creature was cast for its warp cost, it also gains trample and haste until end of turn.

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.

Vibrant Cityscape

Titan's Strength

Target creature gets +3/+1 until end of turn. Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Slip Through Space

Devoid (This card has no color.)
Target creature can't be blocked this turn.
Draw a card.

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.

Octopus Form

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.

Borne Upon a Wind

You may cast spells this turn as though they had flash.
Draw a card.

Big Score

Taigam, Master Opportunist

Flurry — Whenever you cast your second spell each turn, copy it, then exile the spell you cast with four time counters on it. If it doesn't have suspend, it gains suspend. (At the beginning of its owner's upkeep, they remove a time counter. When the last is removed, they may play it without paying its mana cost. If it's a creature, it has haste.)