msem-instigator

Flying
At the beginning of each combat, target opponent may give themselves a poison counter. If they don't, Tower of Sorrows gets +3/+0 until end of turn.

As an additional cost to cast this spell, exile any number of cards from your graveyard. This spell costs {1} less to cast for each card exiled this way.
All creatures get -3/-3 until end of turn.

Deathtouch
Heretic (Whenever you cast a spell that doesn't share a color with this creature, it gets +1/+1 until end of turn.)

Deathtouch

Whenever Toxic Lurker attacks, you may have target creature defending player controls get -2/-1 until end of turn.

Whenever Toxic Miscreant deals combat damage to a player, that player discards a card.

Frenzy 1 (Whenever this creature attacks and isn't blocked, it gets +1/+0 until end of turn.)
Whenever Trading Traitor deals combat damage to a player, you lose life equal to the number of unblocked attacking creatures you control and draw that many cards.

I, II — Mill two cards. You gain 2 life. (Put the top two cards of your library into your graveyard.)
Discovery — During each of your turns, you may cast a permanent spell from your graveyard.

You draw a card, lose 2 life, then create a Vial token. (It's an artifact with “{1}, Sacrifice this and another permanent: Draw a card. Activate only during your turn.”)

Destroy target creature with power less than or equal to the number of creature cards in your graveyard.

At the beginning of your end step, you may mill a card.
{3}{B}, Exile two cards from your graveyard: Target player loses 2 life.

When Trainer of the Abyss dies, create a 1/1 black Demon Hound creature token with deathtouch.

All creatures get -2/-2 until end of turn. Remove two loyalty counters from each planeswalker.

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.

Experience (Whenever this creature attacks, if it has fewer than three +1/+1 counters on it, put a +1/+1 counter on it.)
{1}{W}, Sacrifice a creature or enchantment: Scry 1, then draw a card. Activate only if Trauma Surgeon has a +1/+1 counter on it.

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.

When this creature enters, each opponent loses 2 life and you gain 2 life.
Arise {2}{B}{B} ({2}{B}{B}, Exile this from your graveyard as a sorcery: Create a black token copy of it that's also a Zombie and can't block.)

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.