msem-instigator

Kicker—Sacrifice a creature. (You may sacrifice a creature in addition to any other costs as you cast this spell.)
You draw two cards and you lose 2 life. If this spell was kicked, you draw four cards and you lose 4 life instead.

{3}{B}, Discard a card: Each opponent loses 2 life and you gain 2 life.
At the beginning of your upkeep, if there are five or more creature types among cards in your graveyard, you lose 1 life and draw a card.

Destroy target creature with no counters on it and no permanents attached to it.

{1}{B}, Sacrifice a creature: You gain 1 life and draw a card.
{4}{B}, Pay 3 life, Sacrifice Traverse the Endless Well: Return target creature card from your graveyard to the battlefield. Activate only as a sorcery.

Bleed {1}{B} (You may cast this spell for its bleed cost if an opponent lost life this turn.)
Deathtouch
Treacherous Informant enters with two +1/+1 counters on it if you paid its bleed cost.
You may cast spells for their bleed costs if you lost life this turn.

{B}: Treacherous Shade gets +1/+1 until end of turn.
{1}{B}{B}: Treacherous Shade gets +3/+3 until end of turn.

Destroy target creature. Mill a number of cards equal to its power.

When Treacherous Warden enters, search your library for a card, put into your graveyard, then shuffle.
Whenever a creature enters from your graveyard, each opponent loses 2 life and you gain 2 life.

{2}{B}, Sacrifice a creature: Draw a card.

When Trenchbottom Mariners enters, you lose 3 life, mill three cards, and create a Treasure token.
Whenever Trenchbottom Mariners attacks, you may cast a permanent card from your graveyard by sacrificing another artifact in addition to paying its costs.

Each player sacrifices a creature. (Then exile this card. You may cast the artifact later from exile.)

Destroy target creature or planeswalker you don't control. Its controller creates two tapped Treasure tokens.

{2}, Sacrifice another creature: Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

Deathtouch

Return all creature cards from your graveyard to the battlefield, then exile all but one of them.

Once each turn, when you search your library, you may add {B}{B}.

Whenever a creature dealt damage by Truth Extractor this turn dies, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Enchant player
At the beginning of enchanted player's upkeep, they choose one —
• That player reveals their hand and discards a card.
• That player discards a card at random.

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets +1/+0 and has deathtouch. (Any amount of damage it deals to a creature is enough to destroy it.)

Menace
Whenever an opponent discards a card, monstrosity 2. (If this creature isn't monstrous, put two +1/+1 counters on it and it becomes monstrous.)

Choose one —
• Return target creature card from your graveyard to your hand.
• Pay {4}. If you do, return target creature card from your graveyard to the battlefield.

Exile target creature. Its controller may profit. (To profit, create a colorless Gold artifact token with “Sacrifice this artifact: Add one mana of any color.”)

Flying, lifelink
Sacrifice a creature: Until end of turn, Turned Watcher gets +1/+0 and gains “Whenever Turned Watcher deals combat damage to a player, draw a card.”

Choose X. You may choose the same mode more than once.
• Each opponent loses 3 life and you gain 3 life.
• Each opponent sacrifices a nonland permanent and you create a Treasure token.
• Each opponent discards a card and you draw a card.

As an additional cost to cast this spell, exile X cards from your graveyard.
You draw X cards and you lose X life.
Coalesce {8}{B} (You may cast this from your graveyard for {8}{B}. If you do, it enters as a Horror creature after it resolves. Exile it if it would leave the battlefield or not resolve.)