Agent of the Iron Throne

Commander creatures you own have "Whenever an artifact or creature you control is put into a graveyard from the battlefield, each opponent loses 1 life."

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Zulaport Cutthroat

Whenever Zulaport Cutthroat or another creature you control dies, each opponent loses 1 life and you gain 1 life.

Vindictive Vampire

Whenever another creature you control dies, Vindictive Vampire deals 1 damage to each opponent and you gain 1 life.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Syr Konrad, the Grim

Whenever another creature dies, or a creature card is put into a graveyard from anywhere other than the battlefield, or a creature card leaves your graveyard, Syr Konrad, the Grim deals 1 damage to each opponent.
{1}{B}: Each player mills a card. (They each put the top card of their library into their graveyard.)

Sanguinary Priest

Lifelink
Blood Chalice — Whenever another creature you control dies, Sanguinary Priest deals 1 damage to any target.

Nadier's Nightblade

Whenever a token you control leaves the battlefield, each opponent loses 1 life and you gain 1 life.

Falkenrath Noble

Flying
Whenever Falkenrath Noble or another creature dies, target player loses 1 life and you gain 1 life.

Vraan, Executioner Thane

Whenever one or more other creatures you control die, each opponent loses 2 life and you gain 2 life. This ability triggers only once each turn.

Dreadhound

When Dreadhound enters, mill three cards. (Put the top three cards of your library into your graveyard.)
Whenever a creature dies or a creature card is put into a graveyard from a library, each opponent loses 1 life.