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.)

Urborg Scavengers

Whenever Urborg Scavengers enters or attacks, exile target card from a graveyard. Put a +1/+1 counter on Urborg Scavengers.
Urborg Scavengers has flying as long as a card exiled with it has flying. The same is true for first strike, double strike, deathtouch, haste, hexproof, indestructible, lifelink, menace, reach, trample, and vigilance.

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, 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.

Swamp

Promised Kannushi

Soulshift 7 (When this creature dies, you may return target Spirit card with mana value 7 or less from your graveyard to your hand.)

Kura, the Boundless Sky

Flying, deathtouch
When Kura, the Boundless Sky dies, choose one —
• Search your library for up to three land cards, reveal them, put them into your hand, then shuffle.
• Create an X/X green Spirit creature token, where X is the number of lands you control.

Unchecked Growth

Target creature gets +4/+4 until end of turn. If it's a Spirit, it gains trample until end of turn.

Strangleroot Geist

Haste
Undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield under its owner's control with a +1/+1 counter on it.)

Yargle and Multani

Bloodghast

Bloodghast can't block.
Bloodghast has haste as long as an opponent has 10 or less life.
Landfall — Whenever a land you control enters, you may return Bloodghast from your graveyard to the battlefield.

Kodama's Might

Target creature gets +2/+2 until end of turn.
Splice onto Arcane {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.)

Ashen-Skin Zubera

When Ashen-Skin Zubera dies, target opponent discards a card for each Zubera that died this turn.

Forest

Iname, Death Aspect

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

Dripping-Tongue Zubera

When Dripping-Tongue Zubera dies, create a 1/1 colorless Spirit creature token for each Zubera that died this turn.

Lifespinner

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

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.

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.)

Call of the Death-Dweller

Return up to two target creature cards with total mana value 3 or less from your graveyard to the battlefield. Put a deathtouch counter on either of them. Then put a menace counter on either of them.