msem-instigator

Whenever you condemn a creature, each opponent sacrifices a creature.
{4}{B}: Judge target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

When Maven of Fear enters, mill two cards.
Maven of Fear gets +2/+1 and has menace as long as six or more cards are in your graveyard.

Destroy target non-Elf creature. Its controller loses 1 life for each Elf you control.

Menace
Landfall — Whenever a land you control enters, Mawdryk's Elite gets +1/+0 and gains deathtouch until end of turn.

Flying
{2/B}{2/B}, {T}, Sacrifice Meddling Gargoyle: Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. Activate only as a sorcery.

If you would create an Army token while Mehr's Unending Horde is in your graveyard, you may instead return Mehr's Unending Horde from your graveyard to the battlefield.
Counters remain on Mehr's Unending Horde as it moves to any zone other than a player's hand or library.

Lifelink, menace

Mark (Whenever this creature attacks, mark target creature until end of turn.)
Whenever a marked creature dies, put a +1/+1 counter on Mei's Collector.

Each opponent loses 2 life and you gain 2 life. You mill two cards.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Melodae, the Favored can't be blocked by black creatures.
If Melodae would be destroyed, instead sacrifice a creature and Melodae gains indestructible until end of turn.

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.)

Choose one —
• Exile target player's graveyard.
• Target player sacrifices a creature.

Target player reveals their hand and discards all nonland cards that share a name with a card in their graveyard. If no cards were discarded, draw a card.

Target opponent reveals their hand, exiles each nonland card from it, then conjures a card named Data-Point into their hand for each card exiled this way. (It's a sorcery that costs {2} with “Draw a card.”)

Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. You may put a card that has an Adventure that player owns from exile into that player's graveyard.

Whenever one or more creatures attack Menes, the Great Pyramid, create a tapped 2/3 black Mummy creature token.
[+1]: You get an emblem with “Black creatures you control get +1/+1.”
[–3]: Exile target creature card from a graveyard. Create a tapped token that's a copy of it except it's a black Mummy.

Flash
When Mennin Pack enters, each opponent loses 1 life.
When Mennin Pack dies, each opponent discards a card.

Menace

Enchant opponent
Whenever a creature enters under enchanted player's control, that creature gets -0/-2 until end of turn unless that player pays 2 life.

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Mercenary Coercer deals combat damage to a player, that player discards a card.

Golden age (If you cast an instant or sorcery spell, activated a nonmana ability, and attacked this turn, enter a renaissance for this game.)
{2}{B}, Discard a card: Mercenary of the Folded Fan gains indestructible until end of turn. Tap it. If you're in a renaissance, draw a card.

Deathtouch
Sacrifice a creature: Target player mills two cards.

Whenever Merchant of Flesh or another creature you control dies, create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)
{B}, Sacrifice two Treasures: Each opponent sacrifices a creature.

Whenever Merciless Bandit or another creature you control dies, each opponent loses 1 life and you gain 1 life.

When Merciless Blackguard enters, each player sacrifices a creature. For each creature token sacrificed this way, you may create a Treasure token.