msem-instigator

Butcher deals 3 damage to target player. (Cast a copy of this spell once while this creature is on the battlefield.)

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature gets -2/-2.
Whenever enchanted creature blocks, its controller loses 2 life.

Flying
Whenever Buzzing Flitter attacks, you may pay {G}. If you do, untap target permanent.

By Blood and Fire deals 3 damage to any target. Up to one target creature seeks valor. (Give it that Oath Aura. Fulfill it by it dealing combat damage to a player to create a 2/1 white Soldier token.)

Foretell {2}{U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)
Put target nonland permanent on top of its owner's library.
Scry 2.

Target creature gets +2/+0 and gains haste until end of turn.
Flashback {1}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Flying
When Byte Bug enters, conjure a card named Data-Point into your hand. (It's a sorcery that costs {2} with “Draw a card.”)

Menace, haste
Cadence (Whenever you cast a spell, if its mana value is greater than this creature's power, put a +1/+1 counter on this creature.)

Flying
Whenever you gain life, each opponent loses 1 life.

Defender, reach
Sacrifice Cackling Jack: It deals 3 damage to any target.

When Cadalon Experimenter enters, if you control an artifact, investigate. (Create a colorless Clue artifact token with “{2}, Sacrifice this artifact: Draw a card.”)

Artifact spells you cast cost {1} less to cast.
The first ability of an artifact you activate each turn costs {1} less.

When Caer Crann Borderscout enters, you may search your library for a basic land card, reveal it, and put it into your hand. If you do, shuffle.

Menace
Caer Crann Insurgent gets +2/+0 as long as you've foretold a card or cast a foretold spell this turn.

Vigilance
When this creature enters, you gain life equal to the greatest toughness among other creatures you control.

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

Calamitous Flames deals 6 damage to target creature or planeswalker.
Foretell {2}{R} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

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

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

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

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.

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

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.

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.”)