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

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.

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

Appa, the Vigilant

Flying, vigilance
Whenever Appa or another Ally you control enters, creatures you control get +1/+1 and gain flying and vigilance until end of turn.

Jasmine Dragon Tea Shop

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast an Ally spell or activate an ability of an Ally source.
{5}, {T}: Create a 1/1 white Ally creature token.

Katara, Heroic Healer

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When Katara enters, put a +1/+1 counter on each other creature you control.

Aang and Katara

Whenever Aang and Katara enter or attack, create X 1/1 white Ally creature tokens, where X is the number of tapped artifacts and/or creatures you control.

Explore

You may play an additional land this turn.
Draw a card.

Plains

Heroic Intervention

Permanents you control gain hexproof and indestructible until end of turn.

Razor Rings

Razor Rings deals 4 damage to target attacking or blocking creature. You gain life equal to the excess damage dealt this way.

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on this enchantment.
As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.

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.)

Teo, Spirited Glider

Flying
Whenever one or more creatures you control with flying attack, draw a card, then discard a card. When you discard a nonland card this way, put a +1/+1 counter on target creature you control.

Momo, Playful Pet

Flying, vigilance
When Momo leaves the battlefield, choose one —
• Create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
• Put a +1/+1 counter on target creature you control.
• Scry 2.

Hermitic Herbalist

{T}: Add one mana of any color.
{T}: Add two mana in any combination of colors. Spend this mana only to cast Lesson spells.

Forecasting Fortune Teller

When this creature enters, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Cycle of Renewal

Sacrifice a land. Search your library for up to two basic land cards, put them onto the battlefield tapped, then shuffle.

Rowdy Snowballers

When this creature enters, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Sokka, Lateral Strategist

Vigilance
Whenever Sokka and at least one other creature attack, draw a card.

The Great Henge

This spell costs {X} less to cast, where X is the greatest power among creatures you control.
{T}: Add {G}{G}. You gain 2 life.
Whenever a nontoken creature you control enters, put a +1/+1 counter on it and draw a card.

Forest

Badgermole

When this creature enters, 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.)
Creatures you control with +1/+1 counters on them have trample.

Great Divide Guide

Each land and Ally you control has "{T}: Add one mana of any color."

Sokka's Charge

During your turn, Allies you control have double strike and lifelink.

Island

True Ancestry

Return up to one target permanent card from your graveyard to your hand.
Create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Allied Teamwork

When this enchantment enters, create a 1/1 white Ally creature token.
Allies you control get +1/+1.

Katara, Bending Prodigy

At the beginning of your end step, if Katara is tapped, put a +1/+1 counter on her.
Waterbend {6}: Draw a card. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Deny Entry

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

Flopsie, Bumi's Buddy

When Flopsie enters, put a +1/+1 counter on each creature you control.
Each creature you control with power 4 or greater can't be blocked by more than one creature.

It'll Quench Ya!

Counter target spell unless its controller pays {2}.

Sokka, Wolf Cove's Protector

Vigilance (Attacking doesn't cause this creature to tap.)

United Front

Create X 1/1 white Ally creature tokens, then put a +1/+1 counter on each creature you control.

Obscuring Haze

If you control a commander, you may cast this spell without paying its mana cost.
Prevent all damage that would be dealt this turn by creatures your opponents control.

Master Piandao

First strike
Whenever Master Piandao attacks, look at the top four cards of your library. You may reveal an Ally, Equipment, or Lesson card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Seismic Tutelage

Enchant creature
When this Aura enters, put a +1/+1 counter on enchanted creature.
Whenever enchanted creature attacks, double the number of +1/+1 counters on it.

Jeong Jeong's Deserters

When this creature enters, put a +1/+1 counter on target creature.

Invasion Tactics

When this enchantment enters, creatures you control get +2/+2 until end of turn.
Whenever one or more Allies you control deal combat damage to a player, draw a card.

Thriving Heath

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

North Pole Gates

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

Suki, Courageous Rescuer

Other creatures you control get +1/+0.
Whenever another permanent you control leaves the battlefield during your turn, create a 1/1 white Ally creature token. This ability triggers only once each turn.

Thriving Grove

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

Katara, the Fearless

If a triggered ability of an Ally you control triggers, that ability triggers an additional time.

Yip Yip!

Target creature you control gets +2/+2 until end of turn. If that creature is an Ally, it also gains flying until end of turn.

Arcane Signet

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

Earthbender Ascension

When this enchantment enters, earthbend 2. Then search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Landfall — Whenever a land you control enters, put a quest counter on this enchantment. When you do, if it has four or more quest counters on it, put a +1/+1 counter on target creature you control. It gains trample until end of turn.

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.

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.

Raucous Audience

{T}: Add {G}. If you control a creature with power 4 or greater, add {G}{G} instead.

Badgermole Cub

When this creature enters, earthbend 1. (Target land you control becomes a 0/0 creature with haste that's still a land. Put a +1/+1 counter on it. When it dies or is exiled, return it to the battlefield tapped.)
Whenever you tap a creature for mana, add an additional {G}.

Sol Ring

The Earth King

When The Earth King enters, create a 4/4 green Bear creature token.
Whenever one or more creatures you control with power 4 or greater attack, search your library for up to that many basic land cards, put them onto the battlefield tapped, then shuffle.

North Pole Patrol

{T}: Untap another target permanent you control.
Waterbend {3}, {T}: Tap target creature an opponent controls. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Kyoshi Island Plaza

When Kyoshi Island Plaza enters, search your library for up to X basic land cards, where X is the number of Shrines you control. Put those cards onto the battlefield tapped, then shuffle.
Whenever another Shrine you control enters, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

White Lotus Reinforcements

Vigilance
Other Allies you control get +1/+1.

Southern Air Temple

When Southern Air Temple enters, put X +1/+1 counters on each creature you control, where X is the number of Shrines you control.
Whenever another Shrine you control enters, put a +1/+1 counter on each creature you control.

Suki, Kyoshi Warrior

Suki's power is equal to the number of creatures you control.
Whenever Suki attacks, create a 1/1 white Ally creature token that's tapped and attacking.

Path to Redemption

Enchant creature
Enchanted creature can't attack or block.
{5}, Sacrifice this Aura: Exile enchanted creature. Create a 1/1 white Ally creature token. Activate only during your turn.

Yue, the Moon Spirit

Flying, vigilance
Waterbend {5}, {T}: You may cast a noncreature spell from your hand without paying its mana cost. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Earth Kingdom Protectors

Vigilance
Sacrifice this creature: Another target Ally you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Earth King's Lieutenant

Trample
When this creature enters, put a +1/+1 counter on each other Ally creature you control.
Whenever another Ally you control enters, put a +1/+1 counter on this creature.

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.

Kyoshi Village

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

Appa, Steadfast Guardian

Flash
Flying
When Appa enters, airbend any number of other target nonland permanents you control. (Exile them. While each one is exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever you cast a spell from exile, create a 1/1 white Ally creature token.

Descendants' Path

At the beginning of your upkeep, reveal the top card of your library. If it's a creature card that shares a creature type with a creature you control, you may cast it without paying its mana cost. If you don't cast it, put it on the bottom of your library.

Bender's Waterskin

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

The Spirit Oasis

When The Spirit Oasis enters, draw a card for each Shrine you control.
Whenever another Shrine you control enters, draw a card.

Allies at Last

Affinity for Allies (This spell costs {1} less to cast for each Ally you control.)
Up to two target creatures you control each deal damage equal to their power to target creature an opponent controls.

Energybending

Lands you control gain all basic land types until end of turn.
Draw a card.

Meditation Pools

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

Momo, Friendly Flier

Flying
The first non-Lemur creature spell with flying you cast during each of your turns costs {1} less to cast.
Whenever another creature you control with flying enters, Momo gets +1/+1 until end of turn.

Katara, Water Tribe's Hope

Vigilance
When Katara enters, create a 1/1 white Ally creature token.
Waterbend {X}: Creatures you control have base power and toughness X/X until end of turn. X can't be 0. Activate only during your turn. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Avatar Enthusiasts

Whenever another Ally you control enters, put a +1/+1 counter on this creature.

Hakoda, Selfless Commander

Vigilance
You may look at the top card of your library any time.
You may cast Ally spells from the top of your library.
Sacrifice Hakoda: Creatures you control get +0/+5 and gain indestructible until end of turn.

Aang, Air Nomad

Flying (This creature can't be blocked except by creatures with flying or reach.)
Vigilance (Attacking doesn't cause this creature to tap.)
Other creatures you control have vigilance.

Gran-Gran

Whenever Gran-Gran becomes tapped, draw a card, then discard a card.
Noncreature spells you cast cost {1} less to cast as long as there are three or more Lesson cards in your graveyard.

Secret Tunnel

This land can't be blocked.
{T}: Add {C}.
{4}, {T}: Two target creatures you control that share a creature type can't be blocked this turn.

Prosperity

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.