msem-instigator

Enchant creature
When Bloodbriar Blessing enters, draw a card.
Enchanted creature gets +2/+2 and has menace.

Foretell {1}{B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Return up to two target creature cards from your graveyard to your hand.

Haste
Bloodvenge Berserker doesn't untap during its controller's untap step.
Once each turn, when an opponent is dealt damage by another source you control, you may untap Bloodvenge Berserker.

Menace
Caer Crann Insurgent gets +2/+0 as long as you've foretold a card or cast a foretold spell this turn.

When Carrion Scythe enters, if you cast it, you may return target creature card from your graveyard to the battlefield, then attach Carrion Scythe to it.
Equipped creature gets +1/+1 and has deathtouch.
Equip {2}

Equipped creature gets +2/+1.
Whenever equipped creature attacks, you draw a card and you lose 1 life.
Equip Knight or Soldier {1}
Equip {3}

Once each turn, when you foretell a card or cast a foretold spell, you may create a tapped Treasure token. (It's an artifact with “{T}, Sacrifice this artifact: Add one mana of any color.”)

Each opponent discards two cards. If you control a Knight or Soldier, each opponent loses 2 life and you gain 2 life.

Foretell {B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Up to one target creature gets -1/-1 until end of turn. Put a +1/+1 counter on up to one target creature.

Whenever you foretell a card or cast a foretold spell, you draw a card and you lose 2 life.

Flying, deathtouch

When Defiler of Farmsteads enters, each opponent loses 2 life and you gain 2 life.

Menace
When Depraved Archknight enters, each opponent may pay 7 life. For each player that doesn't, you draw seven cards.

Foretell {3}{B} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Each opponent discards three cards.

Menace
When Doomed Questant enters, each opponent sacrifices a creature and discards a card.

Flying, deathtouch
{B}: Emissary of Dreaded Night gets +1/+1 until end of turn. Activate only if Emissary of Dreaded Night is embattled. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Deathtouch
Discard a card: Headless Carriage gains indestructible until end of turn. Tap it.
Ride {2}{B}{B} ({2}{B}{B}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

(Transform this if it's not attached to a creature. Pay {2}{B}{B} as a sorcery to unattach it.)
Enchant creature you control
Belmord Blood-Coach's rider gets +3/+3 and has deathtouch.
Whenever Belmord Blood-Coach's rider attacks, you may return target creature card with mana value less than its rider's power from your graveyard to the battlefield tapped.

Each opponent sacrifices a creature or planeswalker. If you own a foretold card in exile, you gain 4 life.

Destroy target creature or planeswalker. Create a 1/1 black Rat creature token with “This creature can't block.”

When Limbhacker Blade enters, each opponent discards a card.
Equipped creature gets +2/+0.
Equip {2}

Merciless Champion can't block unless you control another Knight or Soldier.

Whenever a creature you control dies, each opponent loses 1 life and you gain 1 life.
{2}{B}: Create a 1/1 black Rat creature token with “This creature can't block.” Activate only if there are five or more creature cards in your graveyard.

Sacrifice a creature: Pale Horse gets +2/+2 until end of turn.
Ride {B} ({B}: Transform this and attach it to target creature you control without a Steed. Ride only as a sorcery.)

(Transform this if it's not attached to a creature. Pay {B} as a sorcery to unattach it.)
Enchant creature you control
Herald of Death's rider gets +1/+1.
Sacrifice a creature: Herald of Death's rider gets +2/+2 until end of turn.