msem-instigator

Play with the top card of your library revealed.
Whenever you draw a card, destroy each creature with the same mana value as that card.

This spell costs {1} less to cast for each card in your graveyard.
Menace

When Ominous Presence enters, search your library for a Curse card, reveal it, then shuffle. If it has mana value 4 or less, you may put it onto the battlefield. Otherwise, put it into your hand.
Ominous Presence gets +1/+1 for each Curse attached to your opponents.

Target creature gets -2/-2 until end of turn.
{3}{B}{B}, Exile Ominous Wind from your graveyard: Each creature gets -2/-2 until end of turn. Activate only as a sorcery.

Post a bounty on target creature you don't control, then each opponent sacrifices a creature. (Put a bounty counter on that creature. It has “When this creature dies, each opponent draws a card” as long as it has a bounty counter on it.)

This spell costs {1}{B} less to cast if it targets a green or white permanent.
Destroy target creature or planeswalker.

For each player, choose a creature or planeswalker that player controls. Each player sacrifices all creatures and planeswalkers they control not chosen this way.
Fuse (You may cast one or both halves of this card from your hand.)

Return target creature card from your graveyard to the battlefield. Then up to one target opponent sacrifices a creature if you control an Angel, Demon, Faerie, or Spirit.

Whenever Ontarachie Hunter attacks, each opponent loses 1 life.
At the beginning of your end step, if an opponent has 10 or less life, transform Ontarachie Hunter.

Flying
Spells your opponents cast cost an additional 2 life to cast.

Return target creature card from your graveyard to the battlefield, then rediscover a creature card. (Look at the top card of your library. You may reveal it and put it into your hand if it's a creature card. Otherwise, put it back or into your graveyard.)

Search your library for a creature or sorcery card, put it into your graveyard, then shuffle.
Reconstruct {2}{B} (You may cast this from your graveyard for its reconstruct cost reduced by the mana value of a permanent you sacrifice as you cast it this way. Then exile this.)

Deathtouch
Whenever Operative SCARY attacks or you cast a green or white spell, you may draw a card. If you do, you lose 2 life.

Lifelink (Damage dealt by this creature also causes you to gain that much life.)
When Ophelia's Neophyte enters, you may have another target creature you control gain lifelink until end of turn.

Voracious 2 (As this enters, you may sacrifice up to two artifacts and/or creatures. This creature enters with that many +1/+1 counters on it.)
When Opportunistic Beast enters, destroy up to one target creature that was dealt damage this turn.

Enchant creature
Enchanted creature gets -3/-3.
When enchanted creature dies, its controller may scry 1.

Ward—Pay 2 life.
When Orchid Suit enters, target opponent reveals their hand, then exiles a nonland card of their choice from it until Orchid Suit leaves the battlefield.

Target creature gets -5/-5 until end of turn.
Judge up to one target creature you control. (Honor it by putting a +1/+1 counter on it or condemn it by sacrificing it to draw a card.)

Whenever Organ Scavenger perseveres, each opponent loses 2 life. (A creature perseveres when it survives damage.)

Whenever you cast a black spell, choose up to X, where X is the number of black mana symbols in that spell's mana cost —
• Target player loses 1 life and you gain 1 life.
• Put a -1/-1 counter on target creature.
• You draw a card and you lose 3 life.
• Exile target card in a graveyard.

Pressure—Reappropriate black. (You may cast this spell by exiling two black cards from your hand and/or graveyard if there are seven or more cards in your graveyard.)
Destroy target creature or planeswalker.

Trample
Orodu, the Onyx Wave can't block.
Whenever Orodu attacks, defending player may sacrifice a creature. If they do, prevent all combat damage Orodu would deal this turn.

Pressure {3}{B} (You may cast this spell for its pressure cost if seven or more cards are in your graveyard.)
When Oryxyth's Brood enters, you draw two cards and you lose 2 life.

Lifelink
At the beginning of your upkeep, Osgaerith Desecrator deals 1 damage to up to one target creature.

Deception {B} ({B}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.)
When Oshiruko Operative enters, target player loses 1 life.