msem-instigator

{B}: Remove a counter from target permanent.
{3}{B}: Move a counter from target permanent onto Ashfeaster Ghouls. Ashfeaster Ghouls can't be blocked this turn.

When Asking Imp enters, an opponent may pay 2 life. If they do, return Asking Imp to its owner's hand.

When Asphodel Gravedealer dies, choose one —
• Put a +1/+1 counter on target creature you control.
• Create a Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Flash
When Assassin of Fahrib enters, choose one —
• Destroy target creature that was dealt damage this turn.
• Scry 2.

Destroy target tapped creature.

Destroy target creature. Create a tapped Treasure token.

Recruit X times. You lose X life. (To recruit, create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)

Menace
Once during each of your turns, when you sacrifice a permanent, you may put a +1/+1 counter on Assimilated Runner.

Target player sacrifices a creature or planeswalker.
Flashback {4}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Deathtouch
Chronicle (As this enters and after your draw step, add a lore counter. Stop after III.)
[Lore I-II] You may sacrifice another creature. If you do, draw a card.
[Lore III] Remove all lore counters from Astral Leech. Each opponent sacrifices a creature.

When Astrid, Disgruntled Princess enters, destroy target creature with mana value less than or equal to the number of Warriors you control.

Destroy target creature.

Target player reveals their hand. You choose a nonland card from it. That player discards that card. Each player loses 1 life.

When Augmented Alchemist enters or dies, create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Flying
When Augur of Bleak Horizons enters, you gain 3 life and you mill three cards.

Mill three cards. You may return a card milled this way to your hand. Each opponent loses 2 life.
Flashback {3}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

{2}: Avaricious Ghul gets +1/+1 until end of turn. If mana from a Treasure was spent to activate this ability, put a +1/+1 counter on Avaricious Ghul instead.

Deathtouch
Tribute 3 (As this creature enters, an opponent of your choice may put three +1/+1 counters on it.)
When Avatar of Amosis enters, if tribute wasn't paid, you may destroy target creature.

Create a 5/3 black Horror creature token.
Flashback {1}{B}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Pressure {3}{B}{B} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
Each player sacrifices a creature. Put a creature card from a graveyard onto the battlefield under your control.

Target opponent shuffles a card from their hand into their library.

Flash
When Axom enters, remove up to three counters from target permanent.
{2}{U}: Return Axom to its owner's hand.

Desecrate (When this creature enters, you may sacrifice an artifact or land.)
When Back-Alley Vandal desecrates a permanent, put a +1/+1 counter on Back-Alley Vandal.

Satrapies you control have “{2}, {T}, Pay 1 life: Draw a card.”
Satrapycycling {2} ({2}, Discard this card: Search your library for a Satrapy card, reveal it, put it into your hand, then shuffle.)

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)