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.

Toph, Earthbending Master

Landfall — Whenever a land you control enters, you get an experience counter.
Whenever you attack, earthbend X, where X is the number of experience counters you have. (Target land you control becomes a 0/0 creature with haste that's still a land. Put X +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)

Azlask, the Swelling Scourge

Whenever Azlask or another colorless creature you control dies, you get an experience counter.
{W}{U}{B}{R}{G}: Creatures you control get +X/+X until end of turn, where X is the number of experience counters you have. Scions and Spawns you control gain indestructible and annihilator 1 until end of turn.

Thriving Bluff

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

The Earth Crystal

Green spells you cast cost {1} less to cast.
If one or more +1/+1 counters would be put on a creature you control, twice that many +1/+1 counters are put on that creature instead.
{4}{G}{G}, {T}: Distribute two +1/+1 counters among one or two target creatures you control.

Daxos the Returned

Whenever you cast an enchantment spell, you get an experience counter.
{1}{W}{B}: Create a white and black Spirit enchantment creature token. It has "This creature's power and toughness are each equal to the number of experience counters you have."

Azula, Ruthless Firebender

Firebending 1 (Whenever this creature attacks, add {R}. This mana lasts until end of combat.)
Whenever Azula attacks, you may discard a card. Then you get an experience counter for each player who discarded a card this turn.
{2}{B}: Until end of turn, Azula gets +1/+1 for each experience counter you have and gains menace.

Thriving Moor

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

Chromatic Lantern

Lands you control have "{T}: Add one mana of any color."
{T}: Add one mana of any color.

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.

Katara, Waterbending Master

Whenever you cast a spell during an opponent's turn, you get an experience counter.
Whenever Katara attacks, you may draw a card for each experience counter you have. If you do, discard a card.

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.

Flash Thompson, Spider-Fan

Flash
When Flash Thompson enters, choose one or both —
• Heckle — Tap target creature.
• Hero Worship — Untap target creature.

Otharri, Suns' Glory

Flying, lifelink, haste
Whenever Otharri attacks, you get an experience counter. Then create a 2/2 red Rebel creature token that's tapped and attacking for each experience counter you have.
{2}{R}{W}, Tap an untapped Rebel you control: Return this card from your graveyard to the battlefield tapped.

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.

Zuko, Firebending Master

First strike
Firebending X, where X is the number of experience counters you have. (Whenever this creature attacks, add X {R}. This mana lasts until end of combat.)
Whenever you cast a spell during combat, you get an experience counter.

Minthara, Merciless Soul

Minthara has ward {X}, where X is the number of experience counters you have.
At the beginning of your end step, if a permanent you controlled left the battlefield this turn, you get an experience counter.
Creatures you control get +1/+0 for each experience counter you have.

Forest

Arcane Signet

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

Island

Kilo, Apogee Mind

Haste
Whenever Kilo becomes tapped, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Swamp

Monk Gyatso

Whenever another creature you control becomes the target of a spell or ability, you may airbend that creature. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Aang, Airbending Master

When Aang enters, airbend another target creature. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever one or more creatures you control leave the battlefield without dying, you get an experience counter.
At the beginning of your upkeep, create a 1/1 white Ally creature token for each experience counter you have.

Mizzix of the Izmagnus

Whenever you cast an instant or sorcery spell with mana value greater than the number of experience counters you have, you get an experience counter.
Instant and sorcery spells you cast cost {1} less to cast for each experience counter you have.

Thespian's Stage

{T}: Add {C}.
{2}, {T}: This land becomes a copy of target land, except it has this ability.

Mountain

Plains

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.

Kelsien, the Plague

Vigilance, haste
Kelsien gets +1/+1 for each experience counter you have.
{T}: Kelsien deals 1 damage to target creature you don't control. When that creature dies this turn, you get an experience counter.

Command Tower

Planetarium of Wan Shi Tong

{1}, {T}: Scry 2.
Whenever you scry or surveil, look at the top card of your library. You may cast that card without paying its mana cost. Do this only once each turn. (Look at the card after you scry or surveil.)

Bender's Waterskin

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

Sol Ring

Meren of Clan Nel Toth

Whenever another creature you control dies, you get an experience counter.
At the beginning of your end step, choose target creature card in your graveyard. If that card's mana value is less than or equal to the number of experience counters you have, return it to the battlefield. Otherwise, put it into your hand.