Appa, Loyal Sky Bison

Flying
Whenever Appa enters or attacks, choose one —
• Target creature you control gains flying until end of turn.
• Airbend another target nonland permanent you control. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)

Spyglass Siren

Flying
When this creature enters, create a Map token. (It's an artifact with "{1}, {T}, Sacrifice this token: Target creature you control explores. Activate only as a sorcery.")

Nurturing Pixie

Flying
When this creature enters, return up to one target non-Faerie, nonland permanent you control to its owner's hand. If a permanent was returned this way, put a +1/+1 counter on this creature.

Glider Staff

When this Equipment enters, airbend up to one target creature. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Equipped creature gets +1/+1 and has flying.
Equip {2}

Rumble Arena

Vigilance
When this land enters, scry 1. (Look at the top card of your library. You may put it on the bottom.)
{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Refute

Counter target spell. Draw a card, then discard a card.

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.

Aang, the Last Airbender

Flying
When Aang enters, airbend up to one other target nonland permanent. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Whenever you cast a Lesson spell, Aang gains lifelink until end of turn.

Negate

Island

Plumecreed Mentor

Flying
Whenever this creature or another creature you control with flying enters, put a +1/+1 counter on target creature you control without flying.

Blossoming Sands

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {G} or {W}.

Empyrean Eagle

Flying
Other creatures you control with flying get +1/+1.

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

Sheltered by Ghosts

Enchant creature you control
When this Aura enters, exile target nonland permanent an opponent controls until this Aura leaves the battlefield.
Enchanted creature gets +1/+0 and has lifelink and ward {2}.

Plains

Stock Up

Look at the top five cards of your library. Put two of them into your hand and the rest on the bottom of your library in any order.