msem-instigator

Whenever Cavern Monstrosity attacks, exile the bottom card of your library. You gain life equal to its mana value.

Flying
Whenever Cavern Scourge attacks, you may exile a card from your graveyard. If you do, you gain 3 life.

Whenever a creature enters, if it entered from a graveyard or a player cast it from a graveyard, return Ceaseless Stalker from your graveyard to the battlefield at the beginning of the next end step.

[+1]: Each opponent loses 1 life and you gain 1 life. Mill a card. If you do, you may shuffle a card from your graveyard into your library.
[0]: Any number of target players each discard a card. If you have an insight counter, return up to one creature card from your graveyard to your hand.
[0]: You get an insight counter.
[–2]: Target creature gets -3/-3 until end of turn.

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}

Target creature gets -1/-2 until end of turn.
Target creature gets +2/+1 until end of turn.

As an additional cost to cast this spell, sacrifice a creature or planeswalker.
Destroy target creature or planeswalker.

When Channeler of the Veil enters, create a 1/1 colorless Construct artifact creature token.
Sacrifice another creature: Each opponent loses 1 life.

Flash
When Charnel Legion enters, destroy target creature or planeswalker an opponent controls that was dealt damage this turn. When you do, you gain 2 life.

Chigau Market Outskirts enters tapped. When it does, choose a creature card name.
{T}: Add {B}.
{1}, {T}, Sacrifice Chigau Market Outskirts: You may cast a creature spell with the chosen name from your graveyard this turn.

When Chigau, the Red Market enters, draw a card, then choose a creature card name.
Once each turn, you may cast a creature spell with the chosen name from your graveyard.

As an additional cost to cast this spell, sacrifice a creature.
Target creature gets -X/-X until end of turn, where X is the sacrificed creature's power.

Whenever another creature you control dies, target player loses 1 life and you gain 1 life.

Flying

Enchant creature
Enchanted creature gets -2/-2.
Mirage—{B}, Discard a card. (You may cast this spell as though it had flash for its mirage cost. If you do, sacrifice it at the beginning of the next cleanup step.)

Return target creature card with power less than or equal to your fealty to Swamps from your graveyard to the battlefield. (Each Swamp you control counts towards your fealty to Swamps.)

At the beginning of your upkeep, you may sacrifice another creature. If that creature had mana value 2 or greater, create a 3/2 colorless Horror creature token. Otherwise, create a 1/1 colorless Human creature token.
Whenever you create a creature token, you may pay 2 life. If you do, put a menace counter on it.

When Chronic Traitor enters, each player sacrifices a creature. If Chronic Traitor's paranoia cost was paid, each player sacrifices two creatures instead.
Paranoia {2}{B}{B} (You may cast this spell for its paranoia cost when a permanent you control leaves the battlefield.)

When Churning Sandwurms enters, remove all counters from target permanent. Put a +1/+1 counter on Churning Sandwurms for each counter removed this way.

Citadel Bagworm gets +0/+1 for each card in your graveyard.
{B}, Discard a card: Switch Citadel Bagworm's power and toughness until end of turn.

When Clawing Shaman enters from your graveyard, you may exile it. If you do, return all creature cards from your graveyard to the battlefield.
{4}{B}{B}{B}, Sacrifice a creature: Return Clawing Shaman from your graveyard to the battlefield. Activate only as a sorcery.

Sacrifice a creature: Surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)

Create a 2/2 black Zombie creature token.
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.)

Target creature gets -4/-4 until end of turn.

Target player reveals two cards at random from their hand. You choose one of them. That player discards that card.