Jeong Jeong, the Deserter

Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
Exhaust — {3}: Put a +1/+1 counter on Jeong Jeong. When you next cast a Lesson spell this turn, copy it and you may choose new targets for the copy.

Thriving Isle

This land enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Wartime Protestors

Haste
Whenever another Ally you control enters, put a +1/+1 counter on that creature and it gains haste until end of turn.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Island

Stormcarved Coast

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

Boiling Rock Prison

This land enters tapped.
{T}: Add {B} or {R}.
{4}, {T}, Sacrifice this land: Draw a card.

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.

Watery Grave

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

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.

The Fire Nation Drill

Trample
When The Fire Nation Drill enters, you may tap it. When you do, destroy target creature with power 4 or less.
{1}: Permanents your opponents control lose hexproof and indestructible until end of turn.
Crew 2

Command Tower

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

Scarring Memories

You may cast this spell as though it had flash if you control an attacking legendary creature.
Target opponent sacrifices a creature of their choice, discards a card, and loses 3 life.

Sakashima of a Thousand Faces

You may have Sakashima enter as a copy of another creature you control, except it has Sakashima's other abilities.
The "legend rule" doesn't apply to permanents you control.
Partner (You can have two commanders if both have partner.)

Wan Shi Tong, Librarian

Flash
Flying, vigilance
When Wan Shi Tong enters, put X +1/+1 counters on him. Then draw half X cards, rounded down.
Whenever an opponent searches their library, put a +1/+1 counter on Wan Shi Tong and draw a card.

Agna Qel'a

This land enters tapped unless you control a basic land.
{T}: Add {U}.
{2}{U}, {T}: Draw a card, then discard a card.

Baron, Airship Kingdom

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

The Unagi of Kyoshi Island

Flash
Ward—Waterbend {4} (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)
Whenever an opponent draws their second card each turn, draw two cards.

Mirror Box

The "legend rule" doesn't apply to permanents you control.
Each legendary creature you control gets +1/+1.
Each nontoken creature you control gets +1/+1 for each other creature you control with the same name as that creature.

Drowned Catacomb

This land enters tapped unless you control an Island or a Swamp.
{T}: Add {U} or {B}.

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.

Chakra Meditation

When this enchantment enters, return up to one target instant or sorcery card from your graveyard to your hand.
Whenever you cast an instant or sorcery spell, draw a card. Then discard a card unless there are three or more Lesson cards in your graveyard.

Vector, Imperial Capital

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

Thriving Moor

This land enters tapped. As it enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Combustion Man

Whenever Combustion Man attacks, destroy target permanent unless its controller has Combustion Man deal damage to them equal to his power.

Mountain

Mai, Scornful Striker

First strike
Whenever a player casts a noncreature spell, they lose 2 life.

Castle Embereth

This land enters tapped unless you control a Mountain.
{T}: Add {R}.
{1}{R}{R}, {T}: Creatures you control get +1/+0 until end of turn.

Heartless Act

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

Serpent of the Pass

If there are three or more Lesson cards in your graveyard, you may cast this spell as though it had flash.
This spell costs {1} less to cast for each noncreature, nonland card in your graveyard.

Azula Always Lies

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

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}.

Sundial of the Infinite

{1}, {T}: End the turn. Activate only during your turn. (Exile all spells and abilities from the stack. Discard down to your maximum hand size. Damage wears off, and "this turn" and "until end of turn" effects end.)

Thriving Bluff

This land enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Professor Zei, Anthropologist

{T}, Discard a card: Draw a card.
{1}, {T}, Sacrifice Professor Zei: Return target instant or sorcery card from your graveyard to your hand. Activate only during your turn.

Searing Blood

Searing Blood deals 2 damage to target creature. When that creature dies this turn, Searing Blood deals 3 damage to the creature's controller.

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.

Shipwreck Marsh

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

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.)

Sokka, Bold Boomeranger

When Sokka enters, discard up to two cards, then draw that many cards.
Whenever you cast an artifact or Lesson spell, put a +1/+1 counter on Sokka.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

White Lotus Tile

This artifact enters tapped.
{T}: Add X mana of any one color, where X is the greatest number of creatures you control that have a creature type in common.

Octopus Form

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.)

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."

Zuko's Exile

Exile target artifact, creature, or enchantment. Its controller creates a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Lightning Strike

Lightning Strike deals 3 damage to any target.

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.

Swamp

Accumulate Wisdom

Look at the top three cards of your library. Put one of those cards into your hand and the rest on the bottom of your library in any order. Put each of those cards into your hand instead if there are three or more Lesson cards in your graveyard.

Epic Downfall

Exile target creature with mana value 3 or greater.

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.

Arcane Signet

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.)

Xander's Lounge

({T}: Add {U}, {B}, or {R}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Planetarium of Wan Shi Tong

{1}, {T}: Scry 2.
Whenever you scry or surveil, look at the top card of your library. You may cast that card without paying its mana cost. Do this only once each turn. (Look at the card after you scry or surveil.)

Mystical Tutor

Search your library for an instant or sorcery card, reveal it, then shuffle and put that card on top.

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.

Ozai's Cruelty

Ozai's Cruelty deals 2 damage to target player. That player discards two cards.

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.)

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.

Barrels of Blasting Jelly

{1}: Add one mana of any color. Activate only once each turn.
{5}, {T}, Sacrifice this artifact: It deals 5 damage to target creature.

Gamble

Search your library for a card, put that card into your hand, discard a card at random, then shuffle.

The Blue Spirit

You may cast the first creature spell you cast each turn as though it had flash.
Whenever a nontoken creature you control enters during combat, draw a card.

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.

Ty Lee, Chi Blocker

Flash
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Ty Lee enters, tap up to one target creature. It doesn't untap during its controller's untap step for as long as you control Ty Lee.

Deadly Rollick

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

Airship Engine Room

This land enters tapped.
{T}: Add {U} or {R}.
{4}, {T}, Sacrifice this land: Draw a card.

Longshot, Rebel Bowman

Reach (This creature can block creatures with flying.)
Noncreature spells you cast cost {1} less to cast.
Whenever you cast a noncreature spell, Longshot deals 2 damage to each opponent.

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.

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.

Vedalken Orrery

You may cast spells as though they had flash.

The Walls of Ba Sing Se

Defender
Other permanents you control have indestructible.

Bender's Waterskin

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

Fierce Guardianship

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

Lost Days

The owner of target creature or enchantment puts it into their library second from the top or on the bottom. You create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Sol Ring

Bolt Bend

This spell costs {3} less to cast if you control a creature with power 4 or greater.
Change the target of target spell or ability with a single target.

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.)

Deny Entry

Counter target creature spell. Draw a card, then discard a card.

Adventurer's Inn

When this land enters, you gain 2 life.
{T}: Add {C}.

Deflecting Swat

If you control a commander, you may cast this spell without paying its mana cost.
You may choose new targets for target spell or ability.

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.

Sulfur Falls

This land enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Haunted Ridge

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

Treno, Dark City

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

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Dragonskull Summit

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

Serpent's Pass

This land enters tapped.
{T}: Add {U} or {B}.
{4}, {T}, Sacrifice this land: Draw a card.

Cruel Tutor

Search your library for a card, then shuffle and put that card on top. You lose 2 life.

Zuko's Conviction

Kicker {4} (You may pay an additional {4} as you cast this spell.)
Return target creature card from your graveyard to your hand. If this spell was kicked, instead put that card onto the battlefield tapped.

Boar-q-pine

Whenever you cast a noncreature spell, put a +1/+1 counter on this creature.

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.)

Ty Lee, Artful Acrobat

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever Ty Lee attacks, you may pay {1}. When you do, target creature can't block this turn.