North Pole Gates

This land enters tapped.
{T}: Add {W} or {U}.
{4}, {T}, Sacrifice this land: Draw a card.

Earth Kingdom Jailer

When this creature enters, exile up to one target artifact, creature, or enchantment an opponent controls with mana value 3 or greater until this creature leaves the battlefield.

Knowledge Seeker

Vigilance
Whenever you draw your second card each turn, put a +1/+1 counter on this creature.
When this creature dies, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Enter the Avatar State

Until end of turn, target creature you control becomes an Avatar in addition to its other types and gains flying, first strike, lifelink, and hexproof. (A creature with hexproof can't be the target of spells or abilities your opponents control.)

Path to Redemption

Enchant creature
Enchanted creature can't attack or block.
{5}, Sacrifice this Aura: Exile enchanted creature. Create a 1/1 white Ally creature token. Activate only during your turn.

Messenger Hawk

Flying
When this creature enters, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")
This creature gets +2/+0 as long as you've drawn two or more cards this turn.

Geyser Leaper

Flying
Waterbend {4}: Draw a card, then discard a card. (While paying a waterbend cost, you can tap your artifacts and creatures to help. Each one pays for {1}.)

Island

Octopus Form

Target creature you control gets +1/+1 and gains hexproof until end of turn. Untap it. (It can't be the target of spells or abilities your opponents control.)

Sokka, Lateral Strategist

Vigilance
Whenever Sokka and at least one other creature attack, draw a card.

Gran-Gran

Whenever Gran-Gran becomes tapped, draw a card, then discard a card.
Noncreature spells you cast cost {1} less to cast as long as there are three or more Lesson cards in your graveyard.

Plains

Otter-Penguin

Whenever you draw your second card each turn, this creature gets +1/+2 until end of turn and can't be blocked this turn.

Forecasting Fortune Teller

When this creature enters, create a Clue token. (It's an artifact with "{2}, Sacrifice this token: Draw a card.")