Cloudchaser Eagle

Flying
When Cloudchaser Eagle enters the battlefield, destroy target enchantment.

Cloudreach Cavalry

As long as you control a Bird, Cloudreach Cavalry gets +2/+2 and has flying.

Oltec Cloud Guard

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

Arcanist's Owl

Flying
When Arcanist's Owl enters the battlefield, look at the top four cards of your library. You may reveal an artifact or enchantment card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Cloudcrest Lake

{T}: Add {C}.
{T}: Add {W} or {U}. Cloudcrest Lake doesn't untap during your next untap step.

Cloud Key

As Cloud Key enters the battlefield, choose artifact, creature, enchantment, instant, or sorcery.
Spells you cast of the chosen type cost {1} less to cast.

Cloudshift

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