Death-Priest of Myrkul

Skeletons, Vampires, and Zombies you control get +1/+1.
At the beginning of your end step, if a creature died this turn, you may pay {1}. If you do, create a 1/1 black Skeleton creature token.

Elas il-Kor, Sadistic Pilgrim

Deathtouch
Whenever another creature you control enters, you gain 1 life.
Whenever another creature you control dies, each opponent loses 1 life.

Luminous Phantom

Flying
Whenever another creature you control leaves the battlefield, you gain 1 life.
If Luminous Phantom would be put into a graveyard from anywhere, exile it instead.

Lunarch Veteran

Whenever another creature you control enters, you gain 1 life.
Disturb {1}{W} (You may cast this card from your graveyard transformed for its disturb cost.)

Lunarch Veteran // Luminous Phantom

Auriok Champion

Protection from black and from red
Whenever another creature enters, you may gain 1 life.

Alabaster Host Sanctifier

Impassioned Orator

Whenever another creature you control enters, you gain 1 life.

Elenda's Hierophant

Flying
Whenever you gain life, put a +1/+1 counter on this creature.
When this creature dies, create X 1/1 white Vampire creature tokens with lifelink, where X is its power.

Mikaeus, the Lunarch

Mikaeus enters with X +1/+1 counters on it.
{T}: Put a +1/+1 counter on Mikaeus.
{T}, Remove a +1/+1 counter from Mikaeus: Put a +1/+1 counter on each other creature you control.

Guide of Souls

Whenever another creature you control enters, you gain 1 life and get {E} (an energy counter).
Whenever you attack, you may pay {E}{E}{E}. When you do, put two +1/+1 counters and a flying counter on target attacking creature. It becomes an Angel in addition to its other types.

Hammers of Moradin

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever this creature attacks, for each opponent, tap up to one target creature that player controls.

Ajani's Sunstriker

Lifelink (Damage dealt by this creature also causes you to gain that much life.)

Lord Jyscal Guado

Flying
At the beginning of each end step, if you put a counter on a creature this turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Felisa, Fang of Silverquill

Flying
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever a nontoken creature you control dies, if it had counters on it, create X tapped 2/1 white and black Inkling creature tokens with flying, where X is the number of counters it had on it.

Aerith Gainsborough

Lifelink
Whenever you gain life, put a +1/+1 counter on Aerith Gainsborough.
When Aerith Gainsborough dies, put X +1/+1 counters on each legendary creature you control, where X is the number of +1/+1 counters on Aerith Gainsborough.