Unclaimed Territory

As Unclaimed Territory enters the battlefield, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type.

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Millicent, Restless Revenant

This spell costs {1} less to cast for each Spirit you control.
Flying
Whenever Millicent, Restless Revenant or another nontoken Spirit you control dies or deals combat damage to a player, create a 1/1 white Spirit creature token with flying.

Remorseful Cleric

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

Shacklegeist

Flying
Shacklegeist can block only creatures with flying.
Tap two untapped Spirits you control: Tap target creature you don't control.

Haunted Library

Whenever a creature an opponent controls dies, you may pay {1}. If you do, create a 1/1 white Spirit creature token with flying.

Spectral Arcanist

Flying
When Spectral Arcanist enters the battlefield, you may cast an instant or sorcery spell with mana value less than or equal to the number of Spirits you control from a graveyard without paying its mana cost. If that spell would be put into a graveyard, exile it instead.

Reconnaissance Mission

Whenever a creature you control deals combat damage to a player, you may draw a card.
Cycling {2} ({2}, Discard this card: Draw a card.)

Ghastly Mimicry

Enchant creature
At the beginning of your upkeep, create a token that's a copy of enchanted creature, except it's a Spirit in addition to its other types.
If Ghastly Mimicry would be put into a graveyard from anywhere, exile it instead.

Mirrorhall Mimic

You may have Mirrorhall Mimic enter the battlefield as a copy of any creature on the battlefield, except it's a Spirit in addition to its other types.
Disturb {3}{U}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Mirrorhall Mimic // Ghastly Mimicry

Patrician Geist

Flying
Other Spirits you control get +1/+1.
Spells you cast from your graveyard cost {1} less to cast.

Ghostly Pilferer

Whenever Ghostly Pilferer becomes untapped, you may pay {2}. If you do, draw a card.
Whenever an opponent casts a spell from anywhere other than their hand, draw a card.
Discard a card: Ghostly Pilferer can't be blocked this turn.

Storm of Souls

Return all creature cards from your graveyard to the battlefield. Each of them is a 1/1 Spirit with flying in addition to its other types. Exile Storm of Souls.

Selfless Spirit

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

Sol Ring

Distant Melody

Choose a creature type. Draw a card for each permanent you control of that type.

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.

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.

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.

Supreme Phantom

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

Drogskol Reinforcements

Melee (Whenever this creature attacks, it gets +1/+1 until end of turn for each opponent you attacked this combat.)
Other Spirits you control have melee.
Prevent all noncombat damage that would be dealt to Spirits you control.

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Drogskol Captain

Flying
Other Spirit creatures you control get +1/+1 and have hexproof. (They can't be the targets of spells or abilities your opponents control.)

Katilda's Rising Dawn

Enchant creature
Enchanted creature has flying, lifelink, and protection from Vampires, and it gets +X/+X, where X is the number of permanents you control that are Spirits and/or enchantments.
If Katilda's Rising Dawn would be put into a graveyard from anywhere, exile it instead.

Katilda, Dawnhart Martyr

Flying, lifelink, protection from Vampires
Katilda, Dawnhart Martyr's power and toughness are each equal to the number of permanents you control that are Spirits and/or enchantments.
Disturb {3}{W}{W} (You may cast this card from your graveyard transformed for its disturb cost.)