Keyword: Flying

Flying
Clockwork Avian enters with four +1/+0 counters on it.
At end of combat, if Clockwork Avian attacked or blocked this combat, remove a +1/+0 counter from it.
, : Put up to X +1/+0 counters on Clockwork Avian. This ability can’t cause the total number of +1/+0 counters on Clockwork Avian to be greater than four. Activate only during your upkeep.

Flying (This creature can’t be blocked except by creatures with flying or reach.)
Whenever a creature dealt damage by Sengir Vampire this turn dies, put a +1/+1 counter on Sengir Vampire.

Flying

Flying (This creature can’t be blocked except by creatures with flying or reach.)

Flying (This creature can’t be blocked except by creatures with flying or reach.)
When Fog Elemental attacks or blocks, sacrifice it at end of combat.

Flying
Sacrifice a creature: Fallen Angel gets +2/+1 until end of turn.

Flying

Flying
Cloud Elemental can block only creatures with flying.

Flying
: Untap Vigilant Drake.

Flying
: Untap Blizzard Elemental.

Flying (This creature can’t be blocked except by creatures with flying or reach.)

Flying
: Put Wayward Soul on top of its owner’s library.

Flying
When you cast a creature spell, sacrifice Skittering Skirge.

Flying
Cloud Djinn can block only creatures with flying.

Flying (This creature can’t be blocked except by creatures with flying or reach.)
Sacrifice Spiketail Hatchling: Counter target spell unless its controller pays .

If an opponent has no cards in hand, this spell costs less to cast.
Flying

Flying
, Sacrifice a land: Search your library for a Mercenary permanent card with mana value 2 or less, put it onto the battlefield, then shuffle.

Flying, vigilance

Flying
When Windscouter attacks or blocks, return it to its owner’s hand at end of combat. (Return it only if it’s on the battlefield.)

Flying
Sacrifice Spiketail Drake: Counter target spell unless its controller pays .

Flying
, Sacrifice X lands: Put X +1/+1 counters on Copper-Leaf Angel.

Flying
: Ribbon Snake loses flying until end of turn. Any player may activate this ability.

If an opponent controls seven or more lands, this spell costs less to cast.
Flying
: Avatar of Fury gets +1/+0 until end of turn.

If you have 3 or less life, this spell costs less to cast.
Flying
Avatar of Hope can block any number of creatures.