Nightsoil Kami

Soulshift 5 (When this creature dies, you may return target Spirit card with mana value 5 or less from your graveyard to your hand.)

Deathknell Kami

Flying
{2}: Deathknell Kami gets +1/+1 until end of turn. Sacrifice it at the beginning of the next end step.
Soulshift 1 (When this creature dies, you may return target Spirit card with mana value 1 or less from your graveyard to your 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.)

Gibbering Kami

Flying
Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Forked-Branch Garami

Soulshift 4, soulshift 4 (When this creature dies, you may return up to two target Spirit cards with mana value 4 or less from your graveyard to your hand.)

Burr Grafter

Sacrifice Burr Grafter: Target creature gets +2/+2 until end of turn.
Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Kami of Lunacy

Flying
Soulshift 5 (When this creature dies, you may return target Spirit card with mana value 5 or less from your graveyard to your hand.)

Harbinger of Spring

Protection from non-Spirit creatures
Soulshift 4 (When this creature dies, you may return target Spirit card with mana value 4 or less from your graveyard to your 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.)

Kami of Empty Graves

Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Kami of the Palace Fields

Flying, first strike
Soulshift 5 (When this creature dies, you may return target Spirit card with mana value 5 or less from your graveyard to your hand.)

Rootrunner

{G}{G}, Sacrifice Rootrunner: Put target land on top of its owner's library.
Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Moonlit Strider

Sacrifice Moonlit Strider: Target creature you control gains protection from the color of your choice until end of turn.
Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Pus Kami

{B}, Sacrifice Pus Kami: Destroy target nonblack creature.
Soulshift 6 (When this creature dies, you may return target Spirit card with mana value 6 or less from your graveyard to your hand.)

He Who Hungers

Flying
{1}, Sacrifice a Spirit: Target opponent reveals their hand. You choose a card from it. That player discards that card. Activate only as a sorcery.
Soulshift 4 (When this creature dies, you may return target Spirit card with mana value 4 or less from your graveyard to your hand.)

Hundred-Talon Kami

Flying
Soulshift 4 (When this creature dies, you may return target Spirit card with mana value 4 or less from your graveyard to your hand.)

Karador, Ghost Chieftain

This spell costs {1} less to cast for each creature card in your graveyard.
Once during each of your turns, you may cast a creature spell from your graveyard.

Celestial Kirin

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

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.

Crawling Filth

Fear (This creature can't be blocked except by artifact creatures and/or black creatures.)
Soulshift 5 (When this creature dies, you may return target Spirit card with mana value 5 or less from your graveyard to your hand.)

Scuttling Death

Sacrifice Scuttling Death: Target creature gets -1/-1 until end of turn.
Soulshift 4 (When this creature dies, you may return target Spirit card with mana value 4 or less from your graveyard to your hand.)

Kami of the Tended Garden

At the beginning of your upkeep, sacrifice Kami of the Tended Garden unless you pay {G}.
Soulshift 3 (When this creature dies, you may return target Spirit card with mana value 3 or less from your graveyard to your hand.)

Omarthis, Ghostfire Initiate

Omarthis, Ghostfire Initiate enters the battlefield with X +1/+1 counters on it.
Whenever you put one or more +1/+1 counters on another colorless creature, you may put a +1/+1 counter on Omarthis.
When Omarthis dies, manifest a number of cards from the top of your library equal to the number of counters on it.

Ugin's Conjurant

Ugin's Conjurant enters the battlefield with X +1/+1 counters on it.
If damage would be dealt to Ugin's Conjurant while it has a +1/+1 counter on it, prevent that damage and remove that many +1/+1 counters from Ugin's Conjurant.

Kami of the Honored Dead

Flying
Whenever Kami of the Honored Dead is dealt damage, you gain that much life.
Soulshift 6 (When this creature dies, you may return target Spirit card with mana value 6 or less from your graveyard to your hand.)