Kami of the Waning Moon

Flying
Whenever you cast a Spirit or Arcane spell, target creature gains fear until end of turn. (It can't be blocked except by artifact creatures and/or black creatures.)

Thief of Hope

Whenever you cast a Spirit or Arcane spell, target opponent loses 1 life and you gain 1 life.
Soulshift 2 (When this creature dies, you may return target Spirit card with mana value 2 or less from your graveyard to your hand.)

Cloudhoof Kirin

Flying
Whenever you cast a Spirit or Arcane spell, you may have target player mill X cards, where X is that spell's mana value.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Iname, Life Aspect

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

Bounteous Kirin

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

Soilshaper

Whenever you cast a Spirit or Arcane spell, target land becomes a 3/3 creature until end of turn. It's still a land.

Long-Forgotten Gohei

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

Rukarumel, Biologist

As Rukarumel enters, choose a creature type.
Slivers you control and nontoken creatures you control are the chosen type in addition to their other creature types. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 1/1 colorless Sliver creature token.

Skullmane Baku

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on this creature.
{1}, {T}, Remove X ki counters from this creature: Target creature gets -X/-X until end of turn.

Kami of the Hunt

Whenever you cast a Spirit or Arcane spell, this creature gets +1/+1 until end of turn.

Nikko-Onna

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

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.)

Wear Away

Destroy target artifact or enchantment.
Splice onto Arcane {3}{G} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Briarknit Kami

Whenever you cast a Spirit or Arcane spell, put a +1/+1 counter on target creature.

Kami of Fire's Roar

Whenever you cast a Spirit or Arcane spell, target creature can't block this turn.

King of the Oathbreakers

Flying
Whenever King of the Oathbreakers or another Spirit you control becomes the target of a spell, it phases out. (Treat it and anything attached to it as though they don't exist until your next turn.)
Whenever King of the Oathbreakers or another Spirit you control phases in, create a tapped 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.

Waxmane Baku

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on this creature.
{1}, Remove X ki counters from this creature: Tap X target creatures.

Jaraku the Interloper

Remove a ki counter from Jaraku: Counter target spell unless its controller pays {2}.

Callow Jushi

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on this creature.
At the beginning of the end step, if there are two or more ki counters on this creature, you may flip it.

Callow Jushi // Jaraku the Interloper

Guardian of Solitude

Whenever you cast a Spirit or Arcane spell, target creature gains flying until end of turn.

Yuki-Onna

When this creature enters, destroy target artifact.
Whenever you cast a Spirit or Arcane spell, you may return this creature to its owner's hand.

Elder Pine of Jukai

Whenever you cast a Spirit or Arcane spell, reveal the top three cards of your library. Put all land cards revealed this way into your hand and the rest on the bottom of your library in any order.
Soulshift 2 (When this creature dies, you may return target Spirit card with mana value 2 or less from your graveyard to your hand.)

Ribbons of the Reikai

Sire of the Storm

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

Petalmane Baku

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

Soul of Magma

Whenever you cast a Spirit or Arcane spell, this creature deals 1 damage to target creature.

Selfless Spirit

Flying
Sacrifice this creature: Creatures you control gain indestructible until end of turn.

Hofri Ghostforge

Spirits you control get +1/+1 and have trample and haste.
Whenever another nontoken creature you control dies, exile it. If you do, create a token that's a copy of that creature, except it's a Spirit in addition to its other types and it has "When this token leaves the battlefield, return the exiled card to its owner's graveyard."

Millicent, Restless Revenant

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

Rend Flesh

Blademane Baku

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on this creature.
{1}, Remove X ki counters from this creature: For each counter removed, this creature gets +2/+0 until end of turn.

Azamuki, Treachery Incarnate

Remove a ki counter from Azamuki, Treachery Incarnate: Gain control of target creature until end of turn.

Cunning Bandit

Whenever you cast a Spirit or Arcane spell, you may put a ki counter on Cunning Bandit.
At the beginning of the end step, if there are two or more ki counters on Cunning Bandit, you may flip it.

Cunning Bandit // Azamuki, Treachery Incarnate

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.

Supreme Phantom

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

Loam Dweller

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

Teller of Tales

Flying
Whenever you cast a Spirit or Arcane spell, you may tap or untap target creature.

Celestial Kirin

Flying
Whenever you cast a Spirit or Arcane spell, destroy all permanents with that spell's mana value.

Hikari, Twilight Guardian

Flying
Whenever you cast a Spirit or Arcane spell, you may exile Hikari. If you do, return it to the battlefield under its owner's control at the beginning of the next end step.

Kyoki, Sanity's Eclipse

Whenever you cast a Spirit or Arcane spell, target opponent exiles a card from their hand.

Patriarch's Bidding

Each player chooses a creature type. Each player returns all creature cards of a type chosen this way from their graveyard to the battlefield.

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.

Iname, Death Aspect

When Iname enters, you may search your library for any number of Spirit cards, put them into your graveyard, then shuffle.

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.