Teysa, Orzhov Scion

Sacrifice three white creatures: Exile target creature.
Whenever another black creature you control dies, create a 1/1 white Spirit creature token with flying.

Swamp

Twilight Drover

Whenever a creature token leaves the battlefield, put a +1/+1 counter on this creature.
{2}{W}, Remove a +1/+1 counter from this creature: Create two 1/1 white Spirit creature tokens with flying.

Altar's Reap

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Spirit Bonds

Whenever a nontoken creature you control enters, you may pay {W}. If you do, create a 1/1 white Spirit creature token with flying.
{1}{W}, Sacrifice a Spirit: Target non-Spirit creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Lingering Souls

Create two 1/1 white Spirit creature tokens with flying.
Flashback {1}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Plains

Soul's Attendant

Whenever another creature enters, you may gain 1 life.

Soul Warden

Whenever another creature enters, you gain 1 life.

Geist-Honored Monk

Vigilance
Geist-Honored Monk's power and toughness are each equal to the number of creatures you control.
When this creature enters, create two 1/1 white Spirit creature tokens with flying.

Painter's Servant

As this creature enters, choose a color.
All cards that aren't on the battlefield, spells, and permanents are the chosen color in addition to their other colors.

Spectral Procession

Create three 1/1 white Spirit creature tokens with flying.

Brave the Elements

Choose a color. White creatures you control gain protection from the chosen color until end of turn.

Blighted Steppe

{T}: Add {C}.
{3}{W}, {T}, Sacrifice this land: You gain 2 life for each creature you control.

Secluded Steppe

This land enters tapped.
{T}: Add {W}.
Cycling {W} ({W}, Discard this card: Draw a card.)

Luminous Angel

Flying
At the beginning of your upkeep, you may create a 1/1 white Spirit creature token with flying.