msem-instigator

Whenever you cast a spell, reveal the top card of your library. If a card that shares a card type with that spell was revealed this way, Chaos Tradewinder gains flying until end of turn.

Create a 1/1 red Goblin creature token and a 2/2 white Knight creature token.
Tether to artifact (Then if you cast this from your hand, you may exile it tethered to an artifact you control. When it dies, you may cast this from exile without paying its mana cost.)

This spell costs {2} less to cast if you've cast a blue noncreature spell this turn. The same is true for a red noncreature spell.
Menace

Reach
When Chaparral Hunter enters, if a permanent you controlled died this turn, draw a card and you gain 3 life.

Chapel Warden gets +1/+1 and has vigilance as long as you control another Soldier.
{R}, {T}: Chapel Warden deals 1 damage to target creature. Tap that creature.

Primal {G} (During your turn, you may cast this spell for {G} instead of playing a land.)
When Charging Nymph enters, it gets +2/+0 and gains haste until end of turn.

Flying
Charm Canary enters with a +1/+1 counter on it.
When Charm Canary leaves the battlefield, you may put a +1/+1 counter on target creature.

Whenever Charmed Sage deals combat damage to a player, draw two cards.

Creatures your opponents control have haste.

{X}, {T}, Sacrifice Chemical Grenade: Up to X target creatures each get -1/-1 until end of turn.

First strike
As long as it's your turn, other creatures you control get +1/+0.

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).

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.

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

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.

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

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.)

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.

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.

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.