Ally

Gather the White Lotus

Create a 1/1 white Ally creature token for each Plains you control. Scry 2. (Look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Turtle-Duck

{3}: Until end of turn, this creature has base power 4 and gains trample.

Food

Unlucky Cabbage Merchant

When this creature enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Whenever you sacrifice a Food, you may search your library for a basic land card and put it onto the battlefield tapped. If you search your library this way, put this creature on the bottom of its owner's library, then shuffle.

Walltop Sentries

Reach, deathtouch
When this creature dies, if there's a Lesson card in your graveyard, you gain 2 life.

Aang, at the Crossroads

Flying
When Aang enters, look at the top five cards of your library. You may put a creature card with mana value 4 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
When another creature you control leaves the battlefield, transform Aang at the beginning of the next upkeep.

Aang, Destined Savior

Flying
Land creatures you control have vigilance.
At the beginning of combat on your turn, earthbend 2. (Target land you control becomes a 0/0 creature with haste that's still a land. Put two +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)

Aang, at the Crossroads // Aang, Destined Savior

Aang, Swift Savior

Flash
Flying
When Aang enters, airbend up to one other target creature or spell. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Waterbend {8}: Transform Aang.

With the death of the moon spirit, the Avatar's tides of vengeance crashed over the Fire Nation fleet.

Aang and La, Ocean's Fury

Reach, trample
Whenever Aang and La attack, put a +1/+1 counter on each tapped creature you control.

Aang, Swift Savior // Aang and La, Ocean's Fury

Abandon Attachments

You may discard a card. If you do, draw two cards.

Clue

Air Nomad Legacy

When this enchantment enters, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Creatures you control with flying get +1/+1.

When the world needed him most, the Avatar returned.

Avatar Aang

Flying, firebending 2
Whenever you waterbend, earthbend, firebend, or airbend, draw a card. Then if you've done all four this turn, transform Avatar Aang.

Aang, Master of Elements

Flying
Spells you cast cost {W}{U}{B}{R}{G} less to cast. (This can reduce generic costs.)
At the beginning of each upkeep, you may transform Aang, Master of Elements. If you do, you gain 4 life, draw four cards, put four +1/+1 counters on him, and he deals 4 damage to each opponent.

Avatar Aang // Aang, Master of Elements

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.

Beifong's Bounty Hunters

Whenever a nonland creature you control dies, earthbend X, where X is that creature's power. (Target land you control becomes a 0/0 creature with haste that's still a land. Put X +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)

Glider Kids

Flying
When this creature enters, scry 1. (Look at the top card of your library. You may put it on the bottom.)

Bitter Work

Whenever you attack a player with one or more creatures with power 4 or greater, draw a card.
Exhaust — {4}: Earthbend 4. Activate only during your turn. (Target land you control becomes a 0/0 creature with haste that's still a land. Put four +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped. Activate each exhaust ability only once.)

Bumi, Unleashed

Trample
When Bumi enters, earthbend 4.
Whenever Bumi deals combat damage to a player, untap all lands you control. After this phase, there is an additional combat phase. Only land creatures can attack during that combat phase.

Cat-Owl

Flying
Whenever this creature attacks, untap target artifact or creature.

Cruel Administrator

Soldier

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.)

Avatar: The Last Airbender