Clue

{2}, Sacrifice this artifact: Draw a card.

"Their chanting grows louder as the tide rises."
—Tamiyo's journal

Innistrad Remastered Tokens

Bloomburrow Commander Tokens

Modern Horizons 3 Tokens

Outlaws of Thunder Junction Tokens

Fallout Tokens

"If you've been at this as long as I have, nothing can surprise you. That's the hope, at least."

Thraben Inspector

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

Tireless Tracker

Landfall — Whenever a land you control enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on this creature.

Ulvenwald Mysteries

Whenever a nontoken creature you control dies, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, create a 1/1 white Human Soldier creature token.

Entry 434: There's more to Avacyn's madness . . .

Tamiyo's Journal

At the beginning of your upkeep, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{T}, Sacrifice three Clues: Search your library for a card, put that card into your hand, then shuffle.

The evidence was overwhelming. Tovolar's howlpack was getting bolder, smarter, and stronger.

Foul Play

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

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

Briarbridge Tracker

Vigilance (Attacking doesn't cause this creature to tap.)
When Briarbridge Tracker enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
As long as you control a token, Briarbridge Tracker gets +2/+0.

Vigilance (Attacking doesn't cause this creature to tap.)
When this creature enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
As long as you control a token, this creature gets +2/+0.

A good courier travels fast and asks no questions.

Byway Courier

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

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

Elmar, Ulvenwald Informant

Haste
Whenever you cast your second spell each turn, untap target creature, then investigate. (Create a colorless Clue artifact token with "{2}, Sacrifice this artifact: Draw a card.")
Friends forever (You can have two commanders if both have friends forever.)

Automated systems at the Tolarian Academy sort new acquisitions for optimal use, determining which should be studied, eaten, or sold.

Academy Manufactor

If you would create a Clue, Food, or Treasure token, instead create one of each.

Tamiyo Meets the Story Circle

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Until your next turn, whenever a creature attacks you or a planeswalker you control, it gets -2/-0 until end of turn.
II — Discard any number of cards, then investigate twice for each card discarded this way.
III — Shuffle up to three target cards from your graveyard into your library.

The investigator felt a pinch on his ankle. When he looked down, something glittered in the sand.

Hard Evidence

Create a 0/3 blue Crab creature token.
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Hostile Investigator

When Hostile Investigator enters the battlefield, target opponent discards a card.
Whenever one or more players discard one or more cards, investigate. This ability triggers only once each turn. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

When this creature enters, target opponent discards a card.
Whenever one or more players discard one or more cards, investigate. This ability triggers only once each turn. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Transmutation Font

{T}: Create your choice of a Blood token, a Clue token, or a Food token.
{3}, {T}, Sacrifice three artifact tokens with different names: Search your library for an artifact card, put it onto the battlefield, then shuffle. Activate only as a sorcery.

"It's funny how rarely folks here think to look up."

Malcolm, the Eyes

Flying, haste
Whenever you cast your second spell each turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Flying, haste
Whenever you cast your second spell each turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Overencumbered

Enchant opponent
When Overencumbered enters the battlefield, enchanted opponent creates a Clue token, a Food token, and a Junk token.
At the beginning of combat on enchanted opponent's turn, that player may pay {1} for each artifact they control. If they don't, creatures can't attack this combat.

Enchant opponent
When this Aura enters, enchanted opponent creates a Clue token, a Food token, and a Junk token.
At the beginning of combat on enchanted opponent's turn, that player may pay {1} for each artifact they control. If they don't, creatures can't attack this combat.

"So long as we've got each other, that's all that matters."

James, Wandering Dad // Follow Him

{T}: Add {C}{C}. Spend this mana only to activate abilities.

Nick Valentine, Private Eye

Nick Valentine, Private Eye can't be blocked except by artifact creatures.
Whenever Nick Valentine or another artifact creature you control dies, you may investigate. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Nick Valentine can't be blocked except by artifact creatures.
Whenever Nick Valentine or another artifact creature you control dies, you may investigate. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Piper Wright, Publick Reporter

Whenever Piper Wright deals combat damage to a player, investigate that many times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on target creature you control.

Whenever Piper Wright deals combat damage to a player, investigate that many times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on target creature you control.

Ballroom

Ballroom enters the battlefield tapped.
{T}: Add {W} or {B}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {W} or {B}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Billiard Room

Billiard Room enters the battlefield tapped.
{T}: Add {B} or {R}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {B} or {R}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Conservatory

Conservatory enters the battlefield tapped.
{T}: Add {G} or {W}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {G} or {W}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Dining Room

Dining Room enters the battlefield tapped.
{T}: Add {R} or {G}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {R} or {G}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Hall

Hall enters the battlefield tapped.
{T}: Add {R} or {W}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {R} or {W}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Kitchen

Kitchen enters the battlefield tapped.
{T}: Add {G} or {U}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {G} or {U}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Library

Library enters the battlefield tapped.
{T}: Add {U} or {R}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {U} or {R}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Lounge

Lounge enters the battlefield tapped.
{T}: Add {B} or {G}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {B} or {G}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Secret Passage

Secret Passage enters the battlefield tapped.
{T}: Add {U} or {B}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {U} or {B}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Study

Study enters the battlefield tapped.
{T}: Add {W} or {U}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

This land enters tapped.
{T}: Add {W} or {U}.
{4}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Carnage Interpreter

When Carnage Interpreter enters the battlefield, discard your hand, then investigate four times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
As long as you have one or fewer cards in hand, Carnage Interpreter gets +2/+2 and has menace.

When this creature enters, discard your hand, then investigate four times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
As long as you have one or fewer cards in hand, this creature gets +2/+2 and has menace.

Lavinia, Foil to Conspiracy

Vigilance
Whenever you cast your second spell each turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
{T}: Add {C}{C}. Activate only during an opponent's turn.

Vigilance
Whenever you cast your second spell each turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{T}: Add {C}{C}. Activate only during an opponent's turn.

Lonis, Genetics Expert

Evolve (Whenever a creature enters the battlefield under your control, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Lonis, investigate that many times.
Whenever you sacrifice a Clue, put a +1/+1 counter on another target creature you control.

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Lonis, investigate that many times.
Whenever you sacrifice a Clue, put a +1/+1 counter on another target creature you control.

Resonance Technician

Flying
When Resonance Technician enters the battlefield, you may discard a card. If you do, investigate twice.
{T}, Tap X untapped artifacts you control: Copy target instant or sorcery spell you control with mana value X. You may choose new targets for the copy.

Flying
When this creature enters, you may discard a card. If you do, investigate twice.
{T}, Tap X untapped artifacts you control: Copy target instant or sorcery spell you control with mana value X. You may choose new targets for the copy.

Syndicate Heavy

Extort (Whenever you cast a spell, you may pay {WB}. If you do, each opponent loses 1 life and you gain that much life.)
At the beginning of each end step, if you gained 4 or more life this turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Extort (Whenever you cast a spell, you may pay {W/B}. If you do, each opponent loses 1 life and you gain that much life.)
At the beginning of each end step, if you gained 4 or more life this turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Morska, Undersea Sleuth

You have no maximum hand size.
At the beginning of your upkeep, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you draw your second card each turn, put two +1/+1 counters on Morska, Undersea Sleuth.

You have no maximum hand size.
At the beginning of your upkeep, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you draw your second card each turn, put two +1/+1 counters on Morska.

Proft brushed past the guards and introduced himself as "the great Detective Proft" without a hint of irony, then identified the culprit within minutes.

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.")

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.")

Sophia, Dogged Detective

When Sophia, Dogged Detective enters the battlefield, create Tiny, a legendary 2/2 green Dog Detective creature token with trample.
{1}, Sacrifice an artifact token: Put a +1/+1 counter on each Dog you control.
Whenever a Dog you control deals combat damage to a player, create a Food token, then investigate.

When Sophia enters, create Tiny, a legendary 2/2 green Dog Detective creature token with trample.
{1}, Sacrifice an artifact token: Put a +1/+1 counter on each Dog you control.
Whenever a Dog you control deals combat damage to a player, create a Food token, then investigate.

Armed with Proof

When Armed with Proof enters the battlefield, investigate twice. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Clues you control are Equipment in addition to their other types and have "Equipped creature gets +2/+0" and equip {2}.

When this enchantment enters, investigate twice. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Clues you control are Equipment in addition to their other types and have "Equipped creature gets +2/+0" and equip {2}.

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.")

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.")

Merchant of Truth

Flying
Whenever a nontoken creature you control dies, investigate.
Clues you control have exalted. (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn for each instance of exalted among permanents you control.)

Serene Sleuth

When Serene Sleuth enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
At the beginning of combat on your turn, investigate for each goaded creature you control. Then each creature you control is no longer goaded.

When this creature enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
At the beginning of combat on your turn, investigate for each goaded creature you control. Then each creature you control is no longer goaded.

"The culprit doesn't seem to care about covering their tracks. Let's hope that's a good thing."
—Morska

Follow the Bodies

Gravestorm (When you cast this spell, copy it for each permanent put into a graveyard from the battlefield this turn.)
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Gravestorm (When you cast this spell, copy it for each permanent put into a graveyard from the battlefield this turn.)
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

When cunning fails, there's always violence.

No Witnesses

Each player who controls the most creatures investigates. Then destroy all creatures. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Each player who controls the most creatures investigates. Then destroy all creatures. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Foreboding Steamboat

When Foreboding Steamboat enters the battlefield, each player chooses two nontoken, non-Vehicle creatures they control. Exile them until Foreboding Steamboat leaves the battlefield.
Whenever Foreboding Steamboat attacks, put a card exiled with it into its owner's graveyard. If you do, investigate.
Crew 2

When this Vehicle enters, each player chooses two nontoken, non-Vehicle creatures they control. Exile them until this Vehicle leaves the battlefield.
Whenever this Vehicle attacks, put a card exiled with it into its owner's graveyard. If you do, investigate.
Crew 2

"If the perfect evidence appears at your feet, your first task is to rule out misdirection."
—The Ravnican Agency of Magicological Investigations handbook

Novice Inspector

When Novice Inspector enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Unshakable Tail

When Unshakable Tail enters the battlefield and at the beginning of your upkeep, surveil 1.
Whenever one or more creature cards are put into your graveyard from your library, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
{2}, Sacrifice a Clue: Return Unshakable Tail from your graveyard to your hand.

When this creature enters and at the beginning of your upkeep, surveil 1.
Whenever one or more creature cards are put into your graveyard from your library, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{2}, Sacrifice a Clue: Return this card from your graveyard to your hand.

For all their differences, Kaya, Kellan, and Agrus Kos agreed on one thing: none of them would rest until Teysa's murderer was brought to justice.

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.")

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.")

"Well, this clearly didn't come from anyone I know..."

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 artifact: Draw a card.")

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.")

Innocuous Researcher

Parley — Whenever Innocuous Researcher attacks, each player reveals the top card of their library. For each nonland card revealed this way, you investigate. Then each player draws a card.
At the beginning of your end step, you may untap all lands you control. If you do, you can't cast spells until your next turn.

Parley — Whenever this creature attacks, each player reveals the top card of their library. For each nonland card revealed this way, you investigate. Then each player draws a card.
At the beginning of your end step, you may untap all lands you control. If you do, you can't cast spells until your next turn.

Case of the Filched Falcon

When this Case enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: 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.

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.

"It's a rare privilege to investigate one's own death."

Cold Case Cracker

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

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

Each time he replayed the attack in his mind, new details emerged.

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 artifact: Draw a card.")

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.")

Proft lit up like a man who had just been handed a glorious and unexpected gift. "I know who's responsible for this," he said. "And I can prove it."

Deduce

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

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

"Half the city had motive. Time to narrow down who also had the means and opportunity."

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 artifact: Draw a card.")

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.")

Forensic Gadgeteer

Whenever you cast an artifact spell, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: 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.

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.

They always think they're better than the local investigators. They're usually right.

Hotshot Investigators

When Hotshot Investigators enters the battlefield, 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 artifact: Draw a card.")

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.")

Mistway Spy

Flying
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 Mistway Spy is turned face up, until end of turn, whenever a creature you control deals combat damage to a player, investigate.

Flying
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, until end of turn, whenever a creature you control deals combat damage to a player, investigate.

"We'll get their statements after they defrost."
—Dvika of the Foundway Associates

Out Cold

This spell can't be countered. (This includes by the ward ability.)
Tap up to two target creatures and put a stun counter on each of them. Investigate. (If a permanent with a stun counter would become untapped, remove one from it instead.)

"To halt these lurid practices, Geralf must be found and made an example of."
—Inquisitor Delmund

Search the Premises

Whenever a creature attacks you or a planeswalker you control, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Whenever a creature attacks you or a planeswalker you control, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

In her line of work, the dead are often better sources than the living.

Homicide Investigator

Whenever one or more nontoken creatures you control die, investigate. This ability triggers only once each turn. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Whenever one or more nontoken creatures you control die, investigate. This ability triggers only once each turn. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Confirm Suspicions

Counter target spell.
Investigate three times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Counter target spell.
Investigate three times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Persuasive Interrogators

When Persuasive Interrogators enters the battlefield, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")
Whenever you sacrifice a Clue, target opponent gets two poison counters. (A player with ten or more poison counters loses the game.)

When this creature enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, target opponent gets two poison counters. (A player with ten or more poison counters loses the game.)

"When all else fails, follow the geist's lantern."
—Vallon, Thraben inspector

Erdwal Illuminator

Flying
Whenever you investigate for the first time each turn, investigate an additional time.