Dorothea's Retribution

Enchant creature
Enchanted creature has "Whenever this creature attacks, create a 4/4 white Spirit creature token with flying that's tapped and attacking. Sacrifice that token at end of combat."
If Dorothea's Retribution would be put into a graveyard from anywhere, exile it instead.

Dorothea, Vengeful Victim

Flying
When Dorothea, Vengeful Victim attacks or blocks, sacrifice it at end of combat.
Disturb {1}{W}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Dorothea, Vengeful Victim // Dorothea's Retribution

Sire of the Storm

Flying
Whenever you cast a Spirit or Arcane spell, you may draw a card.

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.)

Bident of Thassa

Whenever a creature you control deals combat damage to a player, you may draw a card.
{1}{U}, {T}: Creatures your opponents control attack this turn if able.

Angel of Flight Alabaster

Flying
At the beginning of your upkeep, return target Spirit card from your graveyard to your hand.

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.

Unimpeded Trespasser

Uninvited Geist

Skulk (This creature can't be blocked by creatures with greater power.)
When Uninvited Geist deals combat damage to a player, transform it.

Uninvited Geist // Unimpeded Trespasser

Hallowed Haunting

As long as you control seven or more enchantments, creatures you control have flying and vigilance.
Whenever you cast an enchantment spell, create a white Spirit Cleric creature token with "This creature's power and toughness are each equal to the number of Spirits you control."

Rally the Ranks

As Rally the Ranks enters the battlefield, choose a creature type.
Creatures you control of the chosen type get +1/+1.

Roaming Throne

Ward {2}
As Roaming Throne enters the battlefield, choose a creature type.
Roaming Throne is the chosen type in addition to its other types.
If a triggered ability of another creature you control of the chosen type triggers, it triggers an additional time.

Nebelgast Intruder

Flash
Flying
When Nebelgast Intruder enters the battlefield, up to one target creature an opponent controls gets -2/-0 until end of turn.

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.

Oyobi, Who Split the Heavens

Flying
Whenever you cast a Spirit or Arcane spell, create a 3/3 white Spirit creature token with flying.

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.

Vedalken Orrery

You may cast spells as though they had flash.

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.)

Clarion Spirit

Whenever you cast your second spell each turn, create a 1/1 white Spirit creature token with flying.

Ethereal Investigator

Flying
When Ethereal Investigator enters the battlefield, investigate X times, where X is the number of opponents you have. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you draw your second card each turn, create a 1/1 white Spirit creature token with flying.

Spirited Companion

When Spirited Companion enters the battlefield, draw a card.

Favorable Winds

Creatures you control with flying get +1/+1.

Staff of the Storyteller

When Staff of the Storyteller enters the battlefield, create a 1/1 white Spirit creature token with flying.
Whenever you create one or more creature tokens, put a story counter on Staff of the Storyteller.
{W}, {T}, Remove a story counter from Staff of the Storyteller: Draw a card.

Long-Forgotten Gohei

Arcane spells you cast cost {1} less to cast.
Spirit creatures you control get +1/+1.

Kindred Discovery

As Kindred Discovery enters the battlefield, choose a creature type.
Whenever a creature you control of the chosen type enters the battlefield or attacks, draw a card.

Latch Seeker

Drogskol Reaver

Flying, double strike, lifelink
Whenever you gain life, draw a card.

Field of Souls

Whenever a nontoken creature is put into your graveyard from the battlefield, create a 1/1 white Spirit creature token with flying.

Cemetery Illuminator

Flying
Whenever Cemetery Illuminator enters the battlefield or attacks, exile a card from a graveyard.
You may look at the top card of your library any time.
Once each turn, you may cast a spell from the top of your library if it shares a card type with a card exiled with Cemetery Illuminator.

Andúril, Flame of the West

Equipped creature gets +3/+1.
Whenever equipped creature attacks, create two tapped 1/1 white Spirit creature tokens with flying. If that creature is legendary, instead create two of those tokens that are tapped and attacking.
Equip {2}

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 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.

Ribbons of the Reikai

Selfless Spirit

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

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.

Patrician Geist

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

Reflections of Littjara

As Reflections of Littjara enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, copy that spell. (A copy of a permanent spell becomes a token.)

Breath of the Sleepless

You may cast Spirit spells as though they had flash.
Whenever you cast a creature spell during an opponent's turn, tap up to one target creature.

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.

Door of Destinies

As Door of Destinies enters the battlefield, choose a creature type.
Whenever you cast a spell of the chosen type, put a charge counter on Door of Destinies.
Creatures you control of the chosen type get +1/+1 for each charge counter on Door of Destinies.