msem-instigator

When Grim Procession enters, create two 2/2 black Zombie creature tokens.
{2}{B}: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

At the beginning of each end step, if a creature you control died this turn, each opponent loses 2 life.
{3}{B}: Target creature you control gains lifelink until end of turn.

Ward—Pay 2 life. (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays 2 life.)
Heroic — Whenever you cast a spell that targets Hand of Phenax, you draw a card and you lose 1 life. Hand of Phenax gains menace until end of turn.

Whenever Lampad of Anathemas or another enchantment you control enters, target creature an opponent controls gets -1/-1 until end of turn.

Enchant creature
When Mantle of the Returned enters, return target creature card from your graveyard to the battlefield. It's a Zombie in addition to its other types.
Enchanted creature gets +1/+1 for each Zombie you control.

When Memento Gorgon enters, mill X cards, where X is your devotion to black. Then return a card milled this way to your hand. You lose 1 life. (Each {B} in the mana costs of permanents you control counts toward your devotion to black.)

Menace
When Minotaur Skullsmasher enters, choose a nonland card type. Then target opponent reveals their hand. You choose a card of the chosen type from it. That player discards that card.

Deathtouch
When Mire Triton enters, mill two cards and you gain 2 life.

When Miserable Portent enters, create a 1/1 black Harpy creature token with flying.
{3}{B}, Sacrifice Miserable Portent: You draw two cards and you lose 2 life.

{1}{B}, Sacrifice another creature: Put a +1/+1 counter on Nemesis Eidolon. Draw a card. Activate only as a sorcery.

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Each player loses 1 life.
[Lore III] Create a 1/1 black Harpy creature token with flying.

Flying, deathtouch

Target opponent reveals their hand. You choose a nonland card from it. If you can't, they discard a card. Otherwise, that player discards a card, then if they didn't discard the chosen card, you create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Whenever a creature you control dies, draw a card if it had power greater than its base power.

As long as there are three or more creature cards in your graveyard, Returned Minotaur gets +1/+1 and has menace.

Until end of turn, target creature gains deathtouch and “When this creature dies, return it to the battlefield tapped under its owner's control with a +1/+1 counter on it.”

Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] Mill two cards.
[Lore III] Return target creature card from your graveyard to your hand.

Target creature gets -3/-3 until end of turn. Its controller loses 3 life. You mill three cards.

Flying
Tizerus Bats can't block unless you control another creature with flying.

Flying
When Tormentor Harpy enters, if there are three or more creature cards in your graveyard, target creature an opponent controls gets -3/-3 until end of turn.

Colossal 2—{4}{B} (You may cast this for its colossal cost to have it enter with two +1/+1 counters; or pay {4}{B} as a sorcery: Put two +1/+1 counters on it if it has none.)
Lifelink

Flying
Whenever you attack with two or more creatures with flying, each opponent discards a card.

Flash
Enchant creature
Enchanted creature gets +2/+2 and has flying and “At the beginning of your upkeep, you lose 1 life and create a 1/1 black Harpy creature token with flying.”

Colossal 2—{4}{B}{B} (You may cast this for its colossal cost to have it enter with two +1/+1 counters; or pay {4}{B}{B} as a sorcery: Put two +1/+1 counters on it if it has none.)
Menace
When Wretched Catoblepas's colossal ability puts one or more counters on it, each opponent sacrifices a creature.

Zygos, Underworld Scourge's power and toughness are each equal to the number of cards you own in exile and in your graveyard.
Spells you cast have “As an additional cost to cast this spell, you may exile any number of cards from your graveyard. This spell costs {1} less to cast for each card exiled this way.”