Tranquil Cove

Tranquil Cove enters tapped.
When Tranquil Cove enters, you gain 1 life.
{T}: Add {W} or {U}.

Island

Cloudchaser Kestrel

Flying
When Cloudchaser Kestrel enters, destroy target enchantment.
{W}: Target permanent becomes white until end of turn.

Seaside Citadel

Seaside Citadel enters tapped.
{T}: Add {G}, {W}, or {U}.

Scan the Clouds

Draw two cards, then discard two cards. (Then exile this card. You may cast the creature later from exile.)

Tempest Hart

Trample
Whenever you cast a spell with mana value 5 or greater, put a +1/+1 counter on Tempest Hart.

Tempest Hart // Scan the Clouds

Forest

Krosan Cloudscraper

At the beginning of your upkeep, sacrifice Krosan Cloudscraper unless you pay {G}{G}.
Morph {7}{G}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)

Blossoming Sands

Blossoming Sands enters tapped.
When Blossoming Sands enters, you gain 1 life.
{T}: Add {G} or {W}.

Nimbus Swimmer

Flying
Nimbus Swimmer enters with X +1/+1 counters on it.

Riftwing Cloudskate

Flying
When Riftwing Cloudskate enters, return target permanent to its owner's hand.
Suspend 3—{1}{U} (Rather than cast this card from your hand, you may pay {1}{U} and exile it with three time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.)

Cloudblazer

Flying
When Cloudblazer enters, you gain 2 life and draw two cards.

Fog Bank

Defender, flying
Prevent all combat damage that would be dealt to and dealt by Fog Bank.

Oltec Cloud Guard

Flying
When Oltec Cloud Guard enters, create a 1/1 colorless Gnome artifact creature token.

Cloud of Faeries

Flying
When Cloud of Faeries enters, untap up to two lands.
Cycling {2} ({2}, Discard this card: Draw a card.)

Prevent all combat damage that would be dealt this turn.

Plains

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Cloudkin Seer

Flying
When Cloudkin Seer enters, draw a card.

Cloudgoat Ranger

When Cloudgoat Ranger enters, create three 1/1 white Kithkin Soldier creature tokens.
Tap three untapped Kithkin you control: Cloudgoat Ranger gets +2/+0 and gains flying until end of turn.

Lumbering Falls

Lumbering Falls enters tapped.
{T}: Add {G} or {U}.
{2}{G}{U}: Lumbering Falls becomes a 3/3 green and blue Elemental creature with hexproof until end of turn. It's still a land.

Knight of the Holy Nimbus

Flanking (Whenever a creature without flanking blocks this creature, the blocking creature gets -1/-1 until end of turn.)
If Knight of the Holy Nimbus would be destroyed, regenerate it. (Tap it, remove it from combat, and heal all damage on it.)
{2}: Knight of the Holy Nimbus can't be regenerated this turn. Only your opponents may activate this ability.