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.

Garrison Cat

When Garrison Cat dies, create a 1/1 white Human Soldier creature token.

Corpse Knight

Whenever another creature enters the battlefield under your control, each opponent loses 1 life.

Imperious Oligarch

Vigilance
Afterlife 1 (When this creature dies, create a 1/1 white and black Spirit creature token with flying.)

Blood Artist

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

Marionette Apprentice

Fabricate 1 (When this creature enters the battlefield, put a +1/+1 counter on it or create a 1/1 colorless Servo artifact creature token.)
Whenever another creature or artifact you control is put into a graveyard from the battlefield, each opponent loses 1 life.

Teysa Karlov

If a creature dying causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.
Creature tokens you control have vigilance and lifelink.

Cruel Celebrant

Whenever Cruel Celebrant or another creature or planeswalker you control dies, each opponent loses 1 life and you gain 1 life.

Ocelot Pride

First strike, lifelink
Ascend (If you control ten or more permanents, you get the city's blessing for the rest of the game.)
At the beginning of your end step, if you gained life this turn, create a 1/1 white Cat creature token. Then if you have the city's blessing, for each token you control that entered the battlefield this turn, create a token that's a copy of it.

Kambal, Profiteering Mayor

Whenever one or more tokens enter the battlefield under your opponents' control, for each of them, create a tapped token that's a copy of it. This ability triggers only once each turn.
Whenever one or more tokens enter the battlefield under your control, each opponent loses 1 life and you gain 1 life.

Elenda, the Dusk Rose

Lifelink
Whenever another creature dies, put a +1/+1 counter on Elenda, the Dusk Rose.
When Elenda dies, create X 1/1 white Vampire creature tokens with lifelink, where X is Elenda's power.

Pitiless Plunderer

Whenever another creature you control dies, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")