Crystalline Armor

Enchant creature
Enchanted creature gets +1/+1 for each land you control and has trample.

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.

Forest

Saber-Tooth Moose-Lion

Reach
Forestcycling {2} ({2}, Discard this card: Search your library for a Forest card, reveal it, put it into your hand, then shuffle.)

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.

Cracked Earth Technique

Earthbend 3, then earthbend 3. You gain 3 life. (To earthbend 3, target land you control becomes a 0/0 creature with haste that's still a land. Put three +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)

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.)

Walltop Sentries

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

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.")

Rebellious Captives

Exhaust — {6}: Put two +1/+1 counters on this creature, then 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. Activate each exhaust ability only once.)

Rocky Rebuke

Target creature you control deals damage equal to its power to target creature an opponent controls.

Shared Roots

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Sparring Dummy

Defender
{T}: Mill a card. You may put a land card milled this way into your hand. You gain 2 life if a Lesson card is milled this way. (To mill a card, put the top card of your library into your graveyard.)

Aang, A Lot to Learn

Aang has vigilance as long as there's a Lesson card in your graveyard.
Whenever another creature you control dies, put a +1/+1 counter on Aang.