Three Visits

Search your library for a Forest card, put it onto the battlefield, then shuffle.

Rockfall Vale

This land enters tapped unless you control two or more other lands.
{T}: Add {R} or {G}.

Misty Rainforest

{T}, Pay 1 life, Sacrifice this land: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

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}.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Breeding Pool

({T}: Add {G} or {U}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Ketria Triome

({T}: Add {G}, {U}, or {R}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

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.

Stomping Ground

({T}: Add {R} or {G}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Secret of Bloodbending

As an additional cost to cast this spell, you may waterbend {10}.
You control target opponent during their next combat phase. If this spell's additional cost was paid, you control that player during their next turn instead. (You see all cards that player could see and make all decisions for them.)
Exile Secret of Bloodbending.

Dreamroot Cascade

This land enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Frontier Bivouac

This land enters tapped.
{T}: Add {G}, {U}, or {R}.

Spider-Verse

The "legend rule" doesn't apply to Spiders you control.
Whenever you cast a spell from anywhere other than your hand, you may copy it. If you do, you may choose new targets for the copy. If the copy is a permanent spell, it gains haste. Do this only once each turn.

Cycle of Renewal

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

Teachings of the Archaics

If an opponent has more cards in hand than you, draw two cards. Draw three cards instead if an opponent has at least four more cards in hand than you.

Keeper of Secrets

First strike, haste
Symphony of Pain — Whenever you cast a spell from anywhere other than your hand, this creature deals damage equal to that spell's mana value to target opponent.

Arcane Signet

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

Sulfur Falls

This land enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Birds of Paradise

Yavimaya Coast

{T}: Add {C}.
{T}: Add {G} or {U}. This land deals 1 damage to you.

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Wooded Foothills

{T}, Pay 1 life, Sacrifice this land: Search your library for a Mountain or Forest card, put it onto the battlefield, then shuffle.

Illuminate History

Discard any number of cards, then draw that many cards. Then if there are seven or more cards in your graveyard, create a 3/2 red and white Spirit creature token.

Solstice Revelations

Exile cards from the top of your library until you exile a nonland card. You may cast that card without paying its mana cost if the spell's mana value is less than the number of Mountains you control. If you don't cast that card this way, put it into your hand.
Flashback {6}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. This land deals 1 damage to you.

Doc Aurlock, Grizzled Genius

Spells you cast from your graveyard or from exile cost {2} less to cast.
Plotting cards from your hand costs {2} less.

Waterbending Lesson

Draw three cards. Then discard a card unless you waterbend {2}. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Rejuvenating Springs

This land enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Mountain

Spire Garden

This land enters tapped unless you have two or more opponents.
{T}: Add {R} or {G}.

Redirect Lightning

As an additional cost to cast this spell, pay 5 life or pay {2}.
Change the target of target spell or ability with a single target.

Sol Ring

Forest

Steam Vents

({T}: Add {U} or {R}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Cinder Glade

({T}: Add {R} or {G}.)
This land enters tapped unless you control two or more basic lands.

Abandon Attachments

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

Rootbound Crag

This land enters tapped unless you control a Mountain or a Forest.
{T}: Add {R} or {G}.

Training Center

This land enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Scalding Tarn

{T}, Pay 1 life, Sacrifice this land: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

It'll Quench Ya!

Counter target spell unless its controller pays {2}.

Command Tower

Hinterland Harbor

This land enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.