On the Job

Creatures you control get +2/+1 until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Krenko's Buzzcrusher

Flying, trample
When Krenko's Buzzcrusher enters the battlefield, for each player, destroy up to one nonbasic land that player controls. For each land destroyed this way, its controller may search their library for a basic land card, put it onto the battlefield tapped, then shuffle.

Unyielding Gatekeeper

Disguise {1}{W} (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 Unyielding Gatekeeper is turned face up, exile another target nonland permanent. If you controlled it, return it to the battlefield tapped. Otherwise, its controller creates a 2/2 white and blue Detective creature token.

Case of the Pilfered Proof

Whenever a Detective enters the battlefield under your control and whenever a Detective you control is turned face up, put a +1/+1 counter on it.
To solve — You control three or more Detectives. (If unsolved, solve at the beginning of your end step.)
Solved — If one or more tokens would be created under your control, those tokens plus a Clue token are created instead. (It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Auspicious Arrival

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

Plains

Granite Witness

Flying, vigilance
Disguise {W/U}{W/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 Granite Witness is turned face up, you may tap or untap target creature.

Seasoned Consultant

Whenever you attack with three or more creatures, Seasoned Consultant gets +2/+0 until end of turn.

The Chase Is On

Target creature gets +3/+0 and gains first strike until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Person of Interest

When Person of Interest enters the battlefield, suspect it. Create a 2/2 white and blue Detective creature token. (A suspected creature has menace and can't block.)

Neighborhood Guardian

Whenever another creature with power 2 or less enters the battlefield under your control, target creature you control gets +1/+1 until end of turn.

Essence of Antiquity

Disguise {2}{W} (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 Essence of Antiquity is turned face up, creatures you control gain hexproof until end of turn. Untap them.

Red Herring

Haste
Red Herring attacks each combat if able.
{2}, Sacrifice Red Herring: Draw a card.

Mountain

Gearbane Orangutan

Reach
When Gearbane Orangutan enters the battlefield, choose one —
• Destroy up to one target artifact.
• Sacrifice an artifact. If you do, put two +1/+1 counters on Gearbane Orangutan.

Not on My Watch

Crime Novelist

Whenever you sacrifice an artifact, put a +1/+1 counter on Crime Novelist and add {R}.