Soul Shatter

Each opponent sacrifices a creature or planeswalker with the highest mana value among creatures and planeswalkers they control.

Morbid Opportunist

Whenever one or more other creatures die, draw a card. This ability triggers only once each turn.

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

Yahenni, Undying Partisan

Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni, Undying Partisan.
Sacrifice another creature: Yahenni gains indestructible until end of turn.

Eternal Thirst

Enchant creature
Enchanted creature has lifelink and "Whenever a creature an opponent controls dies, put a +1/+1 counter on this creature." (Damage dealt by a creature with lifelink also causes its controller to gain that much life.)

Massacre Girl

Menace
When Massacre Girl enters, each other creature gets -1/-1 until end of turn. Whenever a creature dies this turn, each creature other than Massacre Girl gets -1/-1 until end of turn.

Sign in Blood

Target player draws two cards and loses 2 life.

Cordial Vampire

Whenever Cordial Vampire or another creature dies, put a +1/+1 counter on each Vampire you control.

Victim of Night

Destroy target non-Vampire, non-Werewolf, non-Zombie creature.

Tragic Slip

Target creature gets -1/-1 until end of turn.
Morbid — That creature gets -13/-13 until end of turn instead if a creature died this turn.

Lim-Dûl the Necromancer

Whenever a creature an opponent controls dies, you may pay {1}{B}. If you do, return that card to the battlefield under your control. If it's a creature, it's a Zombie in addition to its other creature types.
{1}{B}: Regenerate target Zombie.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.

Murder

Doom Blade

Damn

Destroy target creature. A creature destroyed this way can't be regenerated.
Overload {2}{W}{W} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Vengeant Vampire

Lifelink
When Vengeant Vampire dies, destroy target creature an opponent controls and you gain 4 life.

Nullpriest of Oblivion

Kicker {3}{B} (You may pay an additional {3}{B} as you cast this spell.)
Lifelink
Menace (This creature can't be blocked except by two or more creatures.)
When this creature enters, if it was kicked, return target creature card from your graveyard to the battlefield.

Malakir Cullblade

Whenever a creature an opponent controls dies, put a +1/+1 counter on Malakir Cullblade.

Deathmark

Gift of Fangs

Enchant creature
Enchanted creature gets +2/+2 as long as it's a Vampire. Otherwise, it gets -2/-2.

Slaughter Specialist

When Slaughter Specialist enters, each opponent creates a 1/1 white Human creature token.
Whenever a creature an opponent controls dies, put a +1/+1 counter on Slaughter Specialist.

Massacre Wurm

When this creature enters, creatures your opponents control get -2/-2 until end of turn.
Whenever a creature an opponent controls dies, that player loses 2 life.

Toshiro Umezawa

Bushido 1 (Whenever this creature blocks or becomes blocked, it gets +1/+1 until end of turn.)
Whenever a creature an opponent controls dies, you may cast target instant card from your graveyard. If that spell would be put into a graveyard, exile it instead.

Swamp

Infernal Grasp

Destroy target creature. You lose 2 life.

Malicious Invader

Flying
Malicious Invader gets +2/+0 as long as an opponent controls a Human.

Innocent Traveler

At the beginning of your upkeep, any opponent may sacrifice a creature of their choice. If no one does, transform Innocent Traveler.