Keyword: Investigate

Other creatures you control enter the battlefield as a copy of Thraben Inspector. (They’re 1/2s with “When this creature enters the battlefield, investigate”.)
, Sacrifice The Inspector Inspector: Draw a card.

Create a 0/3 blue Crab creature token.
Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

When Hostile Investigator 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 “, Sacrifice this artifact: Draw a card.”)

When Hostile Investigator 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 “, Sacrifice this artifact: Draw a card.”)

When Hostile Investigator 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 “, Sacrifice this artifact: Draw a card.”)

Name two Ravnica Guilds. Create two copies that are copies of their gates. (Ravnica guildgates are lands that enter the battlefield tapped and tap for the two colors of the guild.)
Investigate.

Investigate X times, then create an 0/0 Blue Elemental creature token. Put +1/+1 counters on that token equal to the number of Clues you control.

When Impressive Rat dies, put a hole counter on target land you don’t control. Whenever that land becomes tapped, you investigate. (The land continues to intrigue.)

Populate. Proliferate. Investigate.
Regenerate target creature.
Replicate (When you cast this spell, copy it for each time you paid its replicate cost. You may choose new targets for the copy.)

Billiard Room enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

Dining Room enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

Conservatory enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

Flying
When Resonance Technician enters, you may discard a card. If you do, investigate twice.
, 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.

Vigilance
Whenever you cast your second spell each turn, investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)
: Add . Activate only during an opponent’s turn.

Extort (Whenever you cast a spell, you may pay . 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 “, Sacrifice this artifact: Draw a card.”)

Hall enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

When Carnage Interpreter enters, discard your hand, then investigate four times. (To investigate, create a Clue token. It’s an artifact with “, 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.

Kitchen enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

Library enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

Lounge enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

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.

Study enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

Secret Passage enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)

Ballroom enters tapped.
: Add or .
, : Investigate. (Create a Clue token. It’s an artifact with “, Sacrifice this artifact: Draw a card.”)