Vein Ripper

Flying
Ward—Sacrifice a creature.
Whenever a creature dies, target opponent loses 2 life and you gain 2 life.

Case of the Filched Falcon

Clue

When this Case enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
To solve — You control three or more artifacts. (If unsolved, solve at the beginning of your end step.)
Solved — {2}{U}, Sacrifice this Case: Put four +1/+1 counters on target noncreature artifact. It becomes a 0/0 Bird creature with flying in addition to its other types.

Case of the Ransacked Lab

Instant and sorcery spells you cast cost {1} less to cast.
To solve — You've cast four or more instant and sorcery spells this turn. (If unsolved, solve at the beginning of your end step.)
Solved — Whenever you cast an instant or sorcery spell, draw a card.

Cold Case Cracker

Flying
When this creature dies, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Conspiracy Unraveler

Flying
You may collect evidence 10 rather than pay the mana cost for spells you cast. (To collect evidence 10, exile cards with total mana value 10 or greater from your graveyard.)

Coveted Falcon

A Mysterious Creature

Flying
Whenever this creature attacks, gain control of target permanent you own but don't control.
Disguise {1}{U}
When this creature is turned face up, target opponent gains control of any number of target permanents you control. Draw a card for each one they gained control of this way.

Crimestopper Sprite

As an additional cost to cast this spell, you may collect evidence 6. (Exile cards with total mana value 6 or greater from your graveyard.)
Flying
When this creature enters, tap target creature. If evidence was collected, put a stun counter on it. (If a permanent with a stun counter would become untapped, remove one from it instead.)

Auspicious Arrival

Target creature gets +2/+2 until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Cryptic Coat

When this Equipment enters, cloak the top card of your library, then attach this Equipment to it. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)
Equipped creature gets +1/+0 and can't be blocked.
{1}{U}: Return this Equipment to its owner's hand.

Curious Inquiry

Enchant creature
Enchanted creature gets +1/+1 and has "Whenever this creature deals combat damage to a player, investigate." (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Deduce

Draw a card. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Dramatic Accusation

Enchant creature
When this Aura enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.
{U}{U}: Shuffle enchanted creature into its owner's library.

Eliminate the Impossible

Investigate. Creatures your opponents control get -2/-0 until end of turn. If any of them are suspected, they're no longer suspected. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Exit Specialist

This creature can't be blocked by creatures with power 3 or greater.
Disguise {1}{U} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, return another target creature to its owner's hand.

Fae Flight

Flash
Enchant creature
When this Aura enters, enchanted creature gains hexproof until end of turn.
Enchanted creature gets +1/+0 and has flying.

Forensic Gadgeteer

Whenever you cast an artifact spell, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Activated abilities of artifacts you control cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Murders at Karlov Manor