Have

Agency Outfitter

Flying
When this creature enters, you may search your graveyard, hand and/or library for a card named Magnifying Glass and/or a card named Thinking Cap and put them onto the battlefield. If you search your library this way, shuffle.

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.

Tranquil Cove

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {W} or {U}.

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.

Magnifying Glass

{T}: Add {C}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Marketwatch Phantom

Whenever another creature you control with power 2 or less enters, this creature gains flying until end of turn.

Hotshot Investigators

When this creature enters, return up to one other target creature to its owner's hand. If you controlled it, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Officious Interrogation

This spell costs {W}{U} more to cast for each target beyond the first.
Choose any number of target players. Investigate X times, where X is the total number of creatures those players control.

Case of the Pilfered Proof

Whenever a Detective you control enters or 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 token: Draw a card.")

Makeshift Binding

When this enchantment enters, exile target creature an opponent controls until this enchantment leaves the battlefield. You gain 2 life.

Krovod Haunch

Equipped creature gets +2/+0.
{2}, {T}, Sacrifice this Equipment: You gain 3 life.
When this Equipment is put into a graveyard from the battlefield, you may pay {1}{W}. If you do, create two 1/1 white Dog creature tokens.
Equip {2}

Ezrim, Agency Chief

Flying
When Ezrim enters, investigate twice. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{1}, Sacrifice an artifact: Ezrim gains your choice of vigilance, lifelink, or hexproof until end of turn.

Azorius Guildgate

This land enters tapped.
{T}: Add {W} or {U}.

Alquist Proft, Master Sleuth

Vigilance
When Alquist Proft enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{X}{W}{U}{U}, {T}, Sacrifice a Clue: You draw X cards and gain X life.

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.")

Case of the Filched Falcon

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.

Make Your Move

Destroy target artifact, enchantment, or creature with power 4 or greater.

Projektor Inspector

Whenever this creature or another Detective you control enters and whenever a Detective you control is turned face up, you may draw a card. If you do, discard a card.

Griffnaut Tracker

Flying
When this creature enters, exile up to two target cards from a single graveyard.

Jaded Analyst

Defender
Whenever you draw your second card each turn, this creature loses defender and gains vigilance until end of turn.

Private Eye

Other Detectives you control get +1/+1.
Whenever you draw your second card each turn, target Detective can't be blocked this turn.

Island

Plains

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 token: Draw a card.")

Meandering River

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 this creature is turned face up, you may tap or untap target creature.

Thinking Cap

Equipped creature gets +1/+2.
Equip Detective {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

No More Lies

Counter target spell unless its controller pays {3}. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Inside Source

When this creature enters, create a 2/2 white and blue Detective creature token.
{3}, {T}: Target Detective you control gets +2/+0 and gains vigilance until end of turn. Activate only as a sorcery.

Deduce

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

Wrench

Equipped creature gets +1/+1 and has vigilance and "{3}, {T}: Tap target creature."
{2}, Sacrifice this Equipment: Draw a card.
Equip {2}

Wojek Investigator

Flying, vigilance
At the beginning of your upkeep, investigate once for each opponent who has more cards in hand than you. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Perimeter Enforcer

Flying, lifelink
Whenever another Detective you control enters and whenever a Detective you control is turned face up, this creature gets +1/+1 until end of turn.

Proft's Eidetic Memory

When Proft's Eidetic Memory enters, draw a card.
You have no maximum hand size.
At the beginning of combat on your turn, if you've drawn more than one card this turn, put X +1/+1 counters on target creature you control, where X is the number of cards you've drawn this turn minus one.

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.")