msem-instigator

When Cognitive Fumigator enters, target opponent reveals their hand. You may choose a nonland card from it and exile that card. If you do, that player draws a card.
Recite {2}{U} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters or if it would leave the battlefield.)

Vigilance
Whenever Cohorts of the Grove deals combat damage to a player, if you control a creature with power 4 or greater, draw a card.

Poisonous 2 (Whenever this creature deals combat damage to a player, that player gets two poison counters.)
Coil Remnant has deathtouch as long as an opponent is poisoned.

{1}, Exile Coiling Mystic from your graveyard: Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Concord — When Coiling Spiritscale enters, return target permanent card from your graveyard to your hand. If there are four or more card types among permanents you control, you may return that card to the battlefield instead.

Whenever Coincutter Agent attacks, you draw a card and you lose 1 life.

Flash
Enchant creature
Enchanted creature gets -2/-2 and can't block creatures you control.

When Coincutter Fence enters, starting with you, each player may create a 2/1 red Rogue creature token with “This creature can't block.” For each opponent that does, create a Treasure token.

Menace
Whenever Coirchanh deals combat damage to a player, return up to one target creature card with toughness 4 or greater from your graveyard to the battlefield with a finality counter on it.
{1}{G}: This creature gets +0/+2 until end of turn.

This creature has trample as long as there are four or more -1/-1 counters among creatures.
{3}{B}: Put a -1/-1 counter on target creature.

Creatures you control without counters on them get +2/+2.
Whenever you attack, target attacking creature gains trample until end of turn.
At the beginning of your end step, sacrifice this enchantment unless you put two -1/-1 counters on a creature you control.

Tap target creature. It doesn't untap during its controller's next untap step.
Agonize (You may cast this card from your graveyard by putting a -1/-1 counter on a creature you control in addition to paying its other costs. Then exile this card.)

Creatures have “Whenever this creature attacks or blocks, it fights another target creature.”

Equipped creature gets +1/+1 and has vigilance.
Equip {1}

Counter target spell.
Investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

At the beginning of combat on your turn, target creature you control has base power and toughness 4/4 until end of turn.

Haste
Coldhearted Explorer can't block.

Destroy target artifact or enchantment with mana value 4 or less.

Flash
When Collapsed Mine enters, exile another target nonland permanent until Collapsed Mine leaves the battlefield.

When Collapsing Frame enters, search your library for a basic land card, reveal it, put it into your hand, then shuffle.
{2}, Sacrifice Collapsing Frame: Draw a card.

{T}: Add {C}.
{1}, {T}, Return Collapsing Ground to its owner's hand: Add one mana of any color.

Collapsing Ramparts deals damage to target creature equal to twice the number of Satrapies you control.

Whenever a land enters, Collapsing Realities deals 2 damage to each player.

{T}: Add {C}.
{T}, Pay 1 life: Add {B}.
{5}{B}, {T}, Sacrifice Collapsing Ridges: Return target creature card from a graveyard to the battlefield under your control. Activate only as a sorcery.

Haste
When Collapsing Star Viper enters, you may tap target permanent with mana value X or less.
At the beginning of your upkeep, return Collapsing Star Viper to its owner's hand.