Veko, Death’s Doorkeeper

Extort
, Sacrifice a non-Spirit creature: Return target creature card from your graveyard to your hand. It perpetually becomes a Spirit, has base power and toughness 1/1, and gains “You may pay rather than pay this spell’s mana cost.” Activate only as a sorcery.

Ulvenwald Mysteries

Whenever a nontoken creature you control dies, investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this token: Draw a card.”)
Whenever you sacrifice a Clue, create a 1/1 white Human Soldier creature token.

Rakshasa Deathdealer

: Rakshasa Deathdealer gets +2/+2 until end of turn.
: Regenerate Rakshasa Deathdealer.

Explorer’s Cache

Explorer’s Cache enters with two +1/+1 counters on it.
Whenever a creature you control with a +1/+1 counter on it dies, put a +1/+1 counter on Explorer’s Cache.
: Move a +1/+1 counter from Explorer’s Cache onto target creature. Activate only as a sorcery.

Tarrian’s Soulcleaver

Equipped creature has vigilance.
Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature.
Equip

Tarrian’s Soulcleaver

Equipped creature has vigilance.
Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature.
Equip

Tarrian’s Soulcleaver

Equipped creature has vigilance.
Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature.
Equip

Tarrian’s Soulcleaver

Equipped creature has vigilance.
Whenever another artifact or creature is put into a graveyard from the battlefield, put a +1/+1 counter on equipped creature.
Equip

Underbridge Warlock

Deathtouch
When Underbridge Warlock enters, you get a one-time boon with “At the beginning of your end step, if three or more creatures died this turn, each opponent loses 5 life and you gain 5 life.”
At the beginning of your end step, if you have a boon, you mill three cards, draw a card, and lose 2 life.

Ulvenwald Mysteries

Whenever a nontoken creature you control dies, investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this token: Draw a card.”)
Whenever you sacrifice a Clue, create a 1/1 white Human Soldier creature token.