Selfless Spirit

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

Oyobi, Who Split the Heavens

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

Remorseful Cleric

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

Kodama of the Center Tree

Kodama of the Center Tree's power and toughness are each equal to the number of Spirits you control.
Kodama of the Center Tree has soulshift X, where X is the number of Spirits you control. (When this creature dies, you may return target Spirit card with mana value X or less from your graveyard to your hand.)

Iname, Life Aspect

When Iname, Life Aspect dies, you may exile it. If you do, return any number of target Spirit cards from your graveyard to your hand.

Karmic Guide

Flying, protection from black
Echo {3}{W}{W} (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When Karmic Guide enters, return target creature card from your graveyard to the battlefield.

Petalmane Baku

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on Petalmane Baku.
{1}, Remove X ki counters from Petalmane Baku: Add X mana of any one color.

Smothering Tithe

Whenever an opponent draws a card, that player may pay {2}. If the player doesn't, you create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Lifespinner

{T}, Sacrifice three Spirits: Search your library for a legendary Spirit permanent card, put it onto the battlefield, then shuffle.

Kodama of the South Tree

Whenever you cast a Spirit or Arcane spell, each other creature you control gets +1/+1 and gains trample until end of turn.

Morophon, the Boundless

Changeling (This card is every creature type.)
As Morophon, the Boundless enters, choose a creature type.
Spells of the chosen type you cast cost {W}{U}{B}{R}{G} less to cast. This effect reduces only the amount of colored mana you pay.
Other creatures you control of the chosen type get +1/+1.

Supreme Phantom

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

Infernal Kirin

Flying
Whenever you cast a Spirit or Arcane spell, target player reveals their hand and discards all cards with that spell's mana value.

Nikko-Onna

When Nikko-Onna enters, destroy target enchantment.
Whenever you cast a Spirit or Arcane spell, you may return Nikko-Onna to its owner's hand.

Iname as One

When Iname as One enters, if you cast it from your hand, you may search your library for a Spirit permanent card, put it onto the battlefield, then shuffle.
When Iname as One dies, you may exile it. If you do, return target Spirit permanent card from your graveyard to the battlefield.

Skyfire Kirin

Flying
Whenever you cast a Spirit or Arcane spell, you may gain control of target creature with that spell's mana value until end of turn.

Mausoleum Wanderer

Flying
Whenever another Spirit you control enters, 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.

Drogskol Reaver

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

Ribbons of the Reikai

Angel of Flight Alabaster

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

Sire of the Storm

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

Drogskol Cavalry

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

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.)

Rattlechains

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

Keiga, the Tide Star

Flying
When Keiga, the Tide Star dies, gain control of target creature.

Long-Forgotten Gohei

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

Rend Flesh

Bounteous Kirin

Flying
Whenever you cast a Spirit or Arcane spell, you may gain life equal to that spell's mana value.

Loam Dweller

Whenever you cast a Spirit or Arcane spell, you may put a land card from your hand onto the battlefield tapped.

O-Kagachi, Vengeful Kami

Flying, trample
Whenever O-Kagachi, Vengeful Kami deals combat damage to a player, if that player attacked you during their last turn, exile target nonland permanent that player controls.