Battleground Geist

Flying
Other Spirit creatures you control get +1/+0.

Kami of Twisted Reflection

Sacrifice Kami of Twisted Reflection: Return target creature you control to its owner's hand.

Hook-Haunt Drifter

Flying
If Hook-Haunt Drifter would be put into a graveyard from anywhere, exile it instead.

Baithook Angler

Disturb {1}{U} (You may cast this card from your graveyard transformed for its disturb cost.)

Baithook Angler // Hook-Haunt Drifter

Didact Echo

When Didact Echo enters, draw a card.
Descend 4 — Didact Echo has flying as long as there are four or more permanent cards in your graveyard.

Fogwalker

Skulk (This creature can't be blocked by creatures with greater power.)
When Fogwalker enters, target creature an opponent controls doesn't untap during its controller's next untap step.

Dreamcatcher

Whenever you cast a Spirit or Arcane spell, you may sacrifice Dreamcatcher. If you do, draw a card.