msem-instigator

When Caer Crann Warleader enters, distribute three +1/+1 counters among any number of creatures you control.
Embattled creatures you control have trample. (A creature is embattled if it has a counter on it or a permanent you control attached to it.)

Enchant creature
When Cage the Dissenter enters, scry 2.
Enchanted creature doesn't untap during its controller's untap step.

Choose one or both —
• Put target detained creature on top of its owner's library.
• Detain target creature. (Until your next turn, that creature can't attack or block and its activated abilities can't be activated.)

Calamitous Rampage deals 5 damage to any target.
Cycling {G} ({G}, Discard this card: Draw a card.)

Return up to two target creatures and/or artifacts to their owners' hands. For each permanent returned to its owner's hand this way, forebode. (Create a tapped colorless Omen artifact token with “{T}, Discard a card, Sacrifice this artifact: Draw a card.”)

As Calamity Apparition enters, choose fade or linger.
When Calamity Apparition dies,
• Fade — You gain 2 life and scry 2.
• Linger — Put a +1/+1 counter on target creature you control.

Flying
When Calamity Harbinger enters, it deals 4 damage to up to one target creature or planeswalker.

Whenever Calamity Scholar attacks, if you control an artifact, put a +1/+1 counter on it.

I — Exile the top card of your library face down.
II — Exile any number of cards from your hand face down.
III — Calamity of Yore deals damage to target creature or planeswalker equal to the number of cards you own in exile. Return all cards exiled with Calamity of Yore to their owners' hands.

Target creature or planeswalker you control explores. (Reveal the top card of your library. Put it into your hand if it's a land. Otherwise, put a +1/+1 or loyalty counter on that permanent, then you may put that card into your graveyard.)

({T}: Add {W}.)
As Calcified Dunes enters, you may pay 1 life. If you don't, Calcified Dunes enters tapped.

Calciform Wastes enters tapped. When it does, it explores. (Reveal the top card of your library. Put that card into your hand if it's a land. Otherwise, put a +1/+1 counter on this, then you may may put that card into your graveyard.)
{T}: Add {W}.
{2}{W}{W}: Calciform Wastes becomes a Turtle creature. (This effect lasts indefinitely.)

Whenever Caldera Crawlers attacks, you may sacrifice a land or exile a land card from your graveyard. If you do, target creature gets +1/+1 and gains menace until end of turn.

You may cast target instant or sorcery card from your graveyard this turn. If that spell would be put into your graveyard, exile it instead.

Search your library, graveyard, and/or the command zone for a legendary creature card, reveal it, and put it into your hand. If you search your library this way, shuffle.

Call of the Abyss deals 3 damage to any target and you gain 3 life.

Target player mills three cards for each artifact you control.

Return up to one target noncreature, nonland card from your graveyard to your hand.
Call of the Huma deals 4 damage to any target.
Exile Call of the Huma.

Each player sacrifices a creature. Then return a creature card with mana value 3 or less from your graveyard to the battlefield.

Recruit. (Create a 0/0 white Soldier Army creature token, then put a +1/+1 counter on each Army you control.)
Armies you control gain trample until end of turn.

Create a 1/1 colorless Construct Actor creature token. Put a +1/+1 counter on it if you control another Construct.
Compose (Then if you cast this from your hand, exile it and create a Saga token with “r3—You may cast a copy of this card from exile without paying its mana cost.”)

Destroy up to one target creature with flying or enchantment. Create an Idol token. (It's an artifact with “{1}, Sacrifice this artifact: Put a +1/+1 counter on target creature. Activate only as a sorcery.”)

First strike
Whenever you make first contact, Callous Conduit deals 1 damage to target player or planeswalker. (You make first contact the first time each turn you cast a spell with a name not in your graveyard or control already.)

When Callous Renegade enters, you may return target Rebel creature card with mana value 4 or less from your graveyard to the battlefield. It gains haste until end of turn.

Battalion — Whenever Callous Trainer and at least two other creatures attack, create a 1/1 white Warrior creature token that's tapped and attacking.