msem-instigator

Haste
When Blighted Dullahan dies, you draw a card and you lose 1 life.

When Breaker of Secrets enters, each player mills three cards from each of their libraries.
Recite {U} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

Glorious end — When Brutal Champion dies, if it was tapped, each opponent sacrifices a creature.

Whenever a creature enters, if it entered from a graveyard or a player cast it from a graveyard, return Ceaseless Stalker from your graveyard to the battlefield at the beginning of the next end step.

Flying

Haste
Coldhearted Explorer can't block.

{1}{B}, Discard Crusher Claw: Target creature gains winnow until end of turn. (Damage dealt to it also causes its controller to lose that much life.)

Dawson's Marauder can't block.
When Dawson's Marauder attacks, it can't be blocked this turn unless defending player sacrifices an artifact.

Menace
Whenever Despair Scavenger attacks, you may have target creature get -1/-1 until end of turn.

{1}, Sacrifice a creature: Desperate Forsaken gets +1/+1 until end of turn. You gain 1 life.

Haste
Fleeting {B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

Whenever Devourer of Legacy deals combat damage to a player, you may sacrifice it and choose a nonland card name. If you do, search that player's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles, then draws a card for each card exiled from their hand this way.

Lionize {2}{B} ({2}{B}, Exile this card from your hand: Put a +1/+1 counter on target creature and it gains the following ability until end of turn. You may cast this card on a later turn from exile.)
Lifelink

When Exiled Necromancer enters, return target permanent card with mana value 1 or less from your graveyard to the battlefield.

Fiendish Yaoguai can't block.
Scavenge {5}{B} ({5}{B}, Exile this card from your graveyard: Put a number of +1/+1 counters equal to this card's power on target creature. Scavenge only as a sorcery.)

When Fleshwrithe Ghoul enters, each player sacrifices a creature.
Revive {4}{B} ({4}{B}, Exile this card from your graveyard: Create a token that's a copy of it except it has no mana cost. Revive only as a sorcery.)

Menace
Augmented — When Gravitational Ripper enters, if you've spent {W}{U}{B}{R}{G} to cast spells this turn, target opponent sacrifices a creature. If they can't, they discard a card.

When Hashiro's Vanguard enters, each player sacrifices a nontoken creature.

When Herald of Darkness enters, destroy up to one target creature with mana value 3 or less.

When Ink Seer dies, you draw a card, lose 1 life, and create a Treasure token.

Art of war — At the beginning of your end step, if Kurayami Ronin dealt damage to an opponent this turn, you draw a card and you lose 1 life.

Menace
Whenever Lieshi Pariah deals combat damage, you lose that much life unless it's in a pack. (Two or more creatures you control with equal power are in a pack.)

Living Broadcast can't block.
Whenever you cast a spell from exile, you may return Living Broadcast from your graveyard to your hand.

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.

When Moth-Heart Husk dies, create a 1/1 black Spirit creature token with flying.
Revive {3}{B} ({3}{B}, Exile this card from your graveyard: Create a token that's a copy of this card, except it has no mana cost. Activate this ability only any time you could cast a sorcery.)