Dai Li Agents

When this creature enters, earthbend 1, then earthbend 1. (To 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 this creature attacks, each opponent loses X life and you gain X life, where X is the number of creatures you control with +1/+1 counters on them.

Dragonfly Swarm

Flying, ward {1} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {1}.)
This creature's power is equal to the number of noncreature, nonland cards in your graveyard.
When this creature dies, if there's a Lesson card in your graveyard, draw a card.

Earth Kingdom Soldier

Vigilance
When this creature enters, put a +1/+1 counter on each of up to two target creatures you control.

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.

Earth Rumble Wrestlers

Reach
This creature gets +1/+0 and has trample as long as you control a land creature or a land entered the battlefield under your control this turn.

Earth Village Ruffians

When this creature dies, 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.)

Glider Staff

When this Equipment enters, airbend up to one target creature. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Equipped creature gets +1/+1 and has flying.
Equip {2}

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.)

Fire Lord Zuko

Firebending X, where X is Fire Lord Zuko's power. (Whenever this creature attacks, add X {R}. This mana lasts until end of combat.)
Whenever you cast a spell from exile and whenever a permanent you control enters from exile, put a +1/+1 counter on each creature you control.

Spirit

Foggy Swamp Spirit Keeper

Lifelink
Whenever you draw your second card each turn, create a 1/1 colorless Spirit creature token with "This token can't block or be blocked by non-Spirit creatures."

Guru Pathik

When Guru Pathik enters, look at the top five cards of your library. You may reveal a Lesson, Saga, or Shrine card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Whenever you cast a Lesson, Saga, or Shrine spell, put a +1/+1 counter on another target creature you control.

Hama, the Bloodbender

When Hama enters, target opponent mills three cards. Exile up to one noncreature, nonland card from that player's graveyard. For as long as you control Hama, you may cast the exiled card during your turn by waterbending {X} rather than paying its mana cost, where X is its mana value. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Hei Bai, Spirit of Balance

Whenever Hei Bai enters or attacks, you may sacrifice another creature or artifact. If you do, put two +1/+1 counters on Hei Bai.
When Hei Bai leaves the battlefield, put its counters on target creature you control.

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.

Iroh, Grand Lotus

Firebending 2
During your turn, each non-Lesson instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost. (You may cast a card from your graveyard for its flashback cost. Then exile it.)
During your turn, each Lesson card in your graveyard has flashback {1}.

Ally

Iroh, Tea Master

Food

When Iroh enters, create a Food token.
At the beginning of combat on your turn, you may have target opponent gain control of target permanent you control. When you do, create a 1/1 white Ally creature token. Put a +1/+1 counter on that token for each permanent you own that your opponents control.

Avatar: The Last Airbender