Forest

Turtle-Duck

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

Mountain

Uncle Iroh

Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
Lesson spells you cast cost {1} less to cast.

Tiger-Dillo

This creature can't attack or block unless you control another creature with power 4 or greater.

Fire Sages

Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
{1}{R}{R}: Put a +1/+1 counter on this creature.

Origin of Metalbending

Choose one —
• Destroy target artifact or enchantment.
• Put a +1/+1 counter on target creature you control. It gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Omashu City

This land enters tapped.
{T}: Add {R} or {G}.
{4}, {T}, Sacrifice this land: 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.

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.

Combustion Man

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

Ostrich-Horse

When this creature enters, mill three cards. You may put a land card from among them into your hand. If you don't, put a +1/+1 counter on this creature. (To mill three cards, put the top three cards of your library into your graveyard.)

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.)