msem-instigator

When Callow Survivors enters the battlefield, you may return target artifact or enchantment card with mana value 3 or less from your graveyard to the battlefield.

When Campaign Recruiter enters the battlefield, you may search your library for a creature card with first strike, double strike, flying, improve, lifelink, melee, or vigilance, reveal it, put it into your hand, then shuffle.

Flash
When Cane Dancer enters the battlefield, you may cast target blue instant or sorcery card with mana value 2 from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

When Canopy Ratstalker enters the battlefield, look at the top three cards of your library. You may reveal a land card from among them and put it into your hand. Put the rest on the bottom of your library in any order.

Reach
Menagerie — When Canopyctopus enters the battlefield, if there are five or more creature types among creatures you control, reveal the top card of your library. If its mana value is less than or equal to the number of lands you control, draw a card. Otherwise, you may put that card into your graveyard.

Hexproof
When Cantrip Collector enters the battlefield, rediscover an instant card. (Look at the top card of your library. You may reveal it and put it into your hand if it's an instant card. Otherwise, put it back or into your graveyard.)

When Capac's Envoy enters the battlefield, draw a card.
If one or more players would draw a card except the first one they draw in each of their draw steps, instead each player may draw a card.

Flash
Harmony — You may tap or untap target creature.
When Captivating Jester enters the battlefield, harmonize. (Trigger up to one harmony of one permanent you control.)

Primal {W} (During your turn, you may cast this spell for {W} instead of playing a land.)
When Captured Paletusk enters the battlefield, you may search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle. You gain 2 life. Then sacrifice Captured Paletusk if it was cast for its primal cost.

Haste
When Caravan Engulfer enters the battlefield, creatures you don't control can't block this turn.

When Caravan Guard enters the battlefield, for each kind of counter on target permanent, put another counter of that kind on it or remove one from it.

Flash
When Caronas, Eon Wanderer enters the battlefield, you gain 2 life and draw two cards if Caronas, Eon Wanderer isn't on the battlefield.
{2}{W}{U}, Discard two cards: Aetherize Caronas. (To aetherize, create a token that's a copy of it, then exile that token.)

When Carrion Gourmet enters the battlefield, each player sacrifices a creature.
Whenever another creature dies, put a +1/+1 counter on Carrion Gourmet.

When Carrion Sculptor enters the battlefield, create a 2/2 black Zombie creature token.
{2}{B}, Sacrifice a creature: Return target creature card from your graveyard to your hand.
{1}{B}, Exile Carrion Sculptor from your graveyard: Create a tapped 2/2 black Zombie creature token.

When Carrion Scythe enters the battlefield, if you cast it, you may return target creature card from your graveyard to the battlefield, then attach Carrion Scythe to it.
Equipped creature gets +1/+1 and has deathtouch.
Equip {2}

Flash
When Cast Out enters the battlefield, exile target nonland permanent an opponent controls until Cast Out leaves the battlefield.
Cycling {W} ({W}, Discard this card: Draw a card.)

Flying, haste
When Cataclysmic Skytyrant enters the battlefield, sacrifice all other non-Dragon creatures you control. For each creature sacrificed this way, create a 3/3 red Dragon creature token with flying.

Catalina's Turf enters the battlefield tapped.
When Catalina's Turf enters the battlefield, you may mill two cards.
{T}: Add {B} or {R}.

When Cave Eel enters the battlefield, look at the top three cards of your library. Put one on top and the rest on the bottom in any order.

Flash
When Ceaseless Valiant enters the battlefield, another target permanent gains indestructible until end of turn.
Recite {1}{W} (You may cast this creature from your graveyard for its recite cost. If you do, exile it when it enters the battlefield or if it would leave the battlefield.)

Flying
When Celebrant of Jubilation enters the battlefield, untap all creatures you control.
Cycling {2} ({2}, Discard this card: Draw a card.)

(Choose only one work as a sorcery to add its ability.)
When Celebrations of Ferocity enters the battlefield, add {R}{G}. Spend this mana only to cast creature spells.
{4}{R}{R}: Hao'Tai's Wake
At the beginning of combat on your turn, target creature you control becomes a 4/4 red Dragon with flying until end of turn.
{1}{G}: Portrait of Qiyan
Creatures you control enter the battlefield with an additional +1/+1 counter on them.

Flying
When Cerulean Curtain Treasurer enters the battlefield, audition for blue, then audition for blue again. (Create a 1/1 Construct Actor creature token, a Wizard Role giving 2/2 and prowess, or a Warlock Role giving 2/1 and flying. Roles replace older ones.)

Flying
When Cerulean Sovereign enters the battlefield, you may return target creature an opponent controls or instant or sorcery card in your graveyard to its owner's hand.

When Ch'aska Walla Captain enters the battlefield, if you cast it, you may return an enchantment card from your graveyard to the battlefield. When you do, you gain life equal to that enchantment's mana value.