msem-instigator

When Njel Crocodile enters, you may have it fight target creature. (Each deals damage equal to its power to the other.)

Glitch {2} (Remove one [restriction] for each time you pay the glitch cost.)
Destroy target creature [that was dealt damage this turn].

Whenever No-Good Gunpointer attacks, you may pay 3 life. If you do, draw a card.

Wither (This deals damage to creatures in the form of -1/-1 counters.)
{1}{B}: Return Noonfiend from your graveyard to your hand.

Flying

Enchant player
At the beginning of enchanted player's end step, gain control of a permanent they control.

Breach (Whenever this deals combat damage to a player, you may have it become an Aura Curse until your next turn. Attach it to that player.)
At the beginning of your end step, if an opponent is cursed, surveil 2.

When Noxan Zealot enters, create a tapped 5/5 black Demon enchantment creature token.
{T}, Pay 3 life: Target enchantment creature gains menace and deathtouch until end of turn. Activate only as a sorcery.

Noxious Garden enters tapped.
As Noxious Garden enters, choose a color other than black.
{T}: Add {B} or one mana of the chosen color.

Reverberate—Sacrifice a Swamp. (When you cast this spell, copy it if you paid its reverberate cost.)
All creatures get -2/-2 until end of turn.

When Null Paradigm enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)
Whenever you cast a sorcery spell, each opponent loses 1 life and you gain 1 life.

Flying, deathtouch

Target opponent takes an extra turn after this one. Until your next turn, you control that player during extra turns.
Acquiesce (If you cast this spell from your hand, exile it as it resolves. When one or more creatures you control deal combat damage to an opponent, you may cast this card from exile without paying its mana cost.)

Whenever a creature enters, destroy it unless its controller pays 3 life.

Target opponent exiles a card from their hand. Scry 2.
Tether (Then if you cast this from your hand, you may exile it tethered to a creature you control. When it dies, you may cast this from exile without paying its mana cost.)

Other creatures you control get +2/+0.
Creatures your opponents control get -1/-1.
Fleeting {2}{B} (You may cast this spell for its fleeting cost. If you do, sacrifice it at the beginning of the next end step.)

When Occult Mastermind enters, create two 2/2 black Zombie creature tokens. When Occult Mastermind is no longer on the battlefield, sacrifice two Zombies.

Tithe (As you cast this spell, you may tap three artifacts and/or creatures you control.)
Search your library for a card and put that card into your hand, then shuffle. If this spell's tithe was paid, add {B}{B}{B}{B}.

Slipstream (This creature can't be blocked as long as only creatures with slipstream are attacking.)
{T}: Salvage a creature card. (Exile one from your graveyard until this creature leaves the battlefield. Whenever this creature deals combat damage to a player, put a card it salvaged into your hand.)

Whenever you cast a spell, note its colors.
At the beginning of combat on your turn, up to X target creatures get +2/+0 and gain menace until end of turn, where X is the number of colors noted with Off-Set Rumormonger.

When Offer the Heart enters, draw a card, then choose a card name.
Whenever a creature with the chosen name dies, you gain 1 life and may draw a card.

Each player sacrifices a creature. If a player lost 3 or more life this turn, each opponent sacrifices a creature instead.

Target creature gets -X/-X until end of turn, where X is the number of enchantments you control.

When Old-Oath Conviction enters or leaves the battlefield, create a 1/1 white Cleric creature token with lifelink.
{3}{B}, Sacrifice Old-Oath Conviction: Draw a card. Activate only as a sorcery.

Target creature gets -5/-5 until end of turn. Scry 1.