Reassembling Skeleton

{1}{B}: Return this card from your graveyard to the battlefield tapped.

Lord of the Pit

Flying, trample
At the beginning of your upkeep, sacrifice a creature other than Lord of the Pit. If you can't, Lord of the Pit deals 7 damage to you.

Mausoleum Guard

When Mausoleum Guard dies, create two 1/1 white Spirit creature tokens with flying.

Doomed Traveler

When Doomed Traveler dies, create a 1/1 white Spirit creature token with flying.

Unruly Mob

Whenever another creature you control dies, put a +1/+1 counter on Unruly Mob.

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.

Gather the Townsfolk

Create two 1/1 white Human creature tokens.
Fateful hour — If you have 5 or less life, create five of those tokens instead.

Grave Pact

Whenever a creature you control dies, each other player sacrifices a creature of their choice.

Skirsdag High Priest

Morbid — {T}, Tap two untapped creatures you control: Create a 5/5 black Demon creature token with flying. Activate only if a creature died this turn.

Demonlord of Ashmouth

Flying
When Demonlord of Ashmouth enters, exile it unless you sacrifice another creature.
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.)

Requiem Angel

Flying
Whenever another non-Spirit creature you control dies, create a 1/1 white Spirit creature token with flying.

Reaper from the Abyss

Flying
Morbid — At the beginning of each end step, if a creature died this turn, destroy target non-Demon creature.

Plains

Culling the Weak

As an additional cost to cast this spell, sacrifice a creature.
Add {B}{B}{B}{B}.

Village Bell-Ringer

Flash (You may cast this spell any time you could cast an instant.)
When Village Bell-Ringer enters, untap all creatures you control.

Gallows at Willow Hill

{3}, {T}, Tap three untapped Humans you control: Destroy target creature. Its controller creates a 1/1 white Spirit creature token with flying.