msem-instigator

Whenever a player casts an instant or sorcery spell that targets exactly one creature they don't control, you may copy that spell. If you do, you may choose new targets for the copy.

[+1]: Return up to one target Aura card from a graveyard or on the battlefield to its owner's hand.
[–2]: Sacrifice an enchantment. If you do, return target enchantment card from your graveyard to the battlefield.
[–6]: Draw three cards. Until end of turn, you may cast enchantment spells without paying their mana costs.

Whenever a card is put into a graveyard from anywhere, put a +1/+1 counter on Chief Striking Dawn.
{1}{B}{G}, Remove three counters from Chief Striking Dawn: Return a permanent card from your graveyard to the battlefield.

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

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.

When Chiheisen, Terrace of Serenity enters, draw a card, then choose a creature card name.
Spells you cast with the chosen name cost {2} less to cast.

When Chikyu Champion enters, choose up to one for each land you control. Create a creature token for each of the chosen characteristics.
• 3/3 red Elemental Mouse with haste.
• 3/3 white and blue Fox with vigilance.
• 4/4 green Plant Dinosaur with trample.
• 4/4 red Dragon with flying.
• 4/4 blue Turtle with hexproof.
• 5/5 white Bear Beast.

Enchant creature
When Child of the Pack enters, create a 2/2 green Wolf creature token.
Enchanted creature gets +1/+1 for each Wolf you control.

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.

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.

{1}{G}, Discard a card: Target land you control becomes a 3/3 Elemental creature. It's still a land. Exile the top card of your library face down.
Whenever a land creature you control deals combat damage to a player, put a card exiled with Children of Gos into your hand.

Cast this spell only if an opponent controls two or more nonwhite creatures or you control six or more lands.
Create X 1/1 white Bird creature tokens with flying. You gain X life.

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).

When this creature enters, put two -1/-1 counters on a creature you control.
When you put one or more -1/-1 counters on one or more creatures, tap target creature an opponent controls and put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

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.

{G}{G}: Create a 2/2 green Wolf creature token.
{1}{G}{G}: Create Shimaru, the White Wolf, a legendary 3/3 green Wolf creature token with hexproof.
{2}{G}{G}: Creatures you control get +2/+2 and gain trample until end of turn.