msem-instigator

Reach
Spirited (When this creature enters, you may activate one of its activated abilities without paying its costs.)
{3}{G}: Exile up to one target card from a graveyard. Scry 1.

Children of the Void has hexproof as long as it's your turn.
Children of the Void can't attack or block unless you reappropriate (exile exactly two cards from your hand and/or graveyard).

Harmony — Tap target creature. That creature doesn't untap during its controller's next untap step.
When Chilling Musician enters, harmonize. (Trigger up to one harmony of one permanent you control.)

Engorge (As this enters, mill three cards, then exile a card from among the milled cards.)
Spells you cast that share a type with the card Chillwhisper Witch engorged cost {1} less to cast.

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

When Chimera Graft dies, manifest the bottom card of your library. (To manifest a card, put it onto the battlefield face down as a 2/2 creature. Turn it face up any time for its mana cost if it's a creature card.)

Equipped creature gets +4/+3.
Equip—{2}, Put a -1/-1 counter on a creature you control.

Trample
Whenever a lore counter is put on a Saga you control, Chimperial Guard gets +2/+2 until end of turn.

When Chiseled Familiar enters, draw a card.
Sacrifice Chiseled Familiar: You gain 2 life.

Concord — Whenever Chitinborn Sentry attacks, if there are four or more card types among permanents you control, prevent all damage that would be dealt to target attacking creature this turn.

Flying

{1}, Sacrifice a creature: Put a +1/+1 counter on Chitterrax, then each opponent loses 1 life and you gain 1 life.

As an additional cost to cast this spell, discard a card.
Create three 1/1 black Spirit creature tokens with 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.)

Target creature gets +3/+3 until end of turn and must be blocked this turn if able.
Showcase {3}{G}{G} (Then if you cast this for its showcase cost, create a 1/1 red Bard creature token that can't block and exile this. Whenever it attacks, you may cast a free copy of this.)

Enchant creature
When Chords of Order enters, put a +1/+1 counter on enchanted creature.
Whenever enchanted creature attacks, tap up to one target creature without a +1/+1 counter on it, then untap up to one target creature with a +1/+1 counter on it.

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.)

When Chroma's Guidance enters, create a 2/2 green Wolf creature token.
Whenever you create a creature token, put a +1/+1 counter on it.

Sacrifice Chromeleon: Add one mana of any color. Scry 1.

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.)

{2}, {T}, Sacrifice Chronomancer's Bauble: For each permanent with a time counter on it, you may put a time counter on that permanent or remove a time counter from it.

At the beginning of your upkeep, target player mills two cards. If your main library has five or fewer cards in it, that player mills their library instead.

{2/R}{2/R}: Churning Rough-Roller gets +1/+1 and gains double strike until end of turn.

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

When Churning Spellroot enters, create three 1/1 black Worm creature tokens.