Cackling Culprit

Whenever Cackling Culprit or another creature you control dies, you gain 1 life.
{1}{B}: Cackling Culprit gains deathtouch until end of turn.

Panicked Bystander

Whenever Panicked Bystander or another creature you control dies, you gain 1 life.
At the beginning of your end step, if you gained 3 or more life this turn, transform Panicked Bystander.

Panicked Bystander // Cackling Culprit

Braids, Arisen Nightmare

At the beginning of your end step, you may sacrifice an artifact, creature, enchantment, land, or planeswalker. If you do, each opponent may sacrifice a permanent of their choice that shares a card type with it. For each opponent who doesn't, that player loses 2 life and you draw a card.

The Meathook Massacre

When The Meathook Massacre enters, each creature gets -X/-X until end of turn.
Whenever a creature you control dies, each opponent loses 1 life.
Whenever a creature an opponent controls dies, you gain 1 life.

Weatherlight Compleated

Flying
As long as Weatherlight Compleated has four or more phyresis counters on it, it's a Phyrexian creature in addition to its other types.
Whenever a creature you control dies, put a phyresis counter on Weatherlight Compleated. Then draw a card if it has seven or more phyresis counters on it. If it doesn't, scry 1.