Mausoleum Wanderer

Flying
Whenever another Spirit enters the battlefield under your control, Mausoleum Wanderer gets +1/+1 until end of turn.
Sacrifice Mausoleum Wanderer: Counter target instant or sorcery spell unless its controller pays {X}, where X is Mausoleum Wanderer's power.

Empyrean Eagle

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

Nebelgast Herald

Flash (You may cast this spell any time you could cast an instant.)
Flying
Whenever Nebelgast Herald or another Spirit enters the battlefield under your control, tap target creature an opponent controls.

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Rally of Wings

Untap all creatures you control. Creatures you control with flying get +2/+2 until end of turn.

Rattlechains

Flash
Flying
When Rattlechains enters the battlefield, target Spirit gains hexproof until end of turn.
You may cast Spirit spells as though they had flash.

Drogskol Shieldmate

Flash (You may cast this spell any time you could cast an instant.)
When Drogskol Shieldmate enters the battlefield, other creatures you control get +0/+1 until end of turn.

Topplegeist

Flying
When Topplegeist enters the battlefield, tap target creature an opponent controls.
Delirium — At the beginning of each opponent's upkeep, if there are four or more card types among cards in your graveyard, tap target creature that player controls.

Spectral Sailor

Flash (You may cast this spell any time you could cast an instant.)
Flying
{3}{U}: Draw a card.

Spell Queller

Flash
Flying
When Spell Queller enters the battlefield, exile target spell with mana value 4 or less.
When Spell Queller leaves the battlefield, the exiled card's owner may cast that card without paying its mana cost.

Supreme Phantom

Flying
Other Spirits you control get +1/+1.

Hanged Executioner

Flying
When Hanged Executioner enters the battlefield, create a 1/1 white Spirit creature token with flying.
{3}{W}, Exile Hanged Executioner: Exile target creature.

Remorseful Cleric

Flying
Sacrifice Remorseful Cleric: Exile target player's graveyard.

Bygone Bishop

Flying
Whenever you cast a creature spell with mana value 3 or less, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Spectral Shepherd

Flying
{1}{U}: Return target Spirit you control to its owner's hand.

Selfless Spirit

Flying
Sacrifice Selfless Spirit: Creatures you control gain indestructible until end of turn.

Drogskol Cavalry

Flying
Whenever another Spirit enters the battlefield under your control, you gain 2 life.
{3}{W}: Create a 1/1 white Spirit creature token with flying.