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.

Magnetic Snuffler

When this creature enters, return target Equipment card from your graveyard to the battlefield attached to this creature.
Whenever you sacrifice an artifact, put a +1/+1 counter on this creature.

Alley Assailant

This creature enters tapped.
Disguise {4}{B}{B} (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, target opponent loses 3 life and you gain 3 life.

Public Thoroughfare

This land enters tapped.
When this land enters, sacrifice it unless you tap an untapped artifact or land you control.
{T}: Add one mana of any color.

Cryptex

{T}, Collect evidence 3: Add one mana of any color. Put an unlock counter on this artifact. (To collect evidence 3, exile cards with total mana value 3 or greater from your graveyard.)
Sacrifice this artifact: Surveil 3, then draw three cards. Activate only if this artifact has five or more unlock counters on it.

Toxin Analysis

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

Ghost Quarter

{T}: Add {C}.
{T}, Sacrifice this land: Destroy target land. Its controller may search their library for a basic land card, put it onto the battlefield, then shuffle.

Case of the Stashed Skeleton

When this Case enters, create a 2/1 black Skeleton creature token and suspect it. (It has menace and can't block.)
To solve — You control no suspected Skeletons. (If unsolved, solve at the beginning of your end step.)
Solved — {1}{B}, Sacrifice this Case: Search your library for a card, put it into your hand, then shuffle. Activate only as a sorcery.

Case of the Gorgon's Kiss

When this Case enters, destroy up to one target creature that was dealt damage this turn.
To solve — Three or more creature cards were put into graveyards from anywhere this turn. (If unsolved, solve at the beginning of your end step.)
Solved — This Case is a 4/4 Gorgon creature with deathtouch and lifelink in addition to its other types.

Murder

Drag the Canal

Create a 2/2 white and blue Detective creature token. If a creature died this turn, you gain 2 life, surveil 2, then investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Basilica Stalker

Flying
Whenever this creature deals combat damage to a player, you gain 1 life and surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Disguise {4}{B} (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.)

Escape Tunnel

{T}, Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
{T}, Sacrifice this land: Target creature with power 2 or less can't be blocked this turn.

Faerie Snoop

Flying
Disguise {1}{U/B}{U/B} (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, look at the top two cards of your library. Put one into your hand and the other into your graveyard.

Lead Pipe

Equipped creature gets +2/+0.
Whenever equipped creature dies, each opponent loses 1 life.
{2}, Sacrifice this Equipment: Draw a card.
Equip {2}

Island

Deadly Cover-Up

As an additional cost to cast this spell, you may collect evidence 6.
Destroy all creatures. If evidence was collected, exile a card from an opponent's graveyard. Then search its owner's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles, then draws a card for each card exiled from their hand this way.

Snarling Gorehound

Menace
Whenever another creature you control with power 2 or less enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Agency Coroner

{2}{B}, Sacrifice another creature: Draw a card. If the sacrificed creature was suspected, draw two cards instead.

Nightdrinker Moroii

Flying
When this creature enters, you lose 3 life.
Disguise {B}{B} (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.)

Rot Farm Mortipede

Whenever one or more creature cards leave your graveyard, this creature gets +1/+0 and gains menace and lifelink until end of turn.

Reasonable Doubt

Counter target spell unless its controller pays {2}.
Suspect up to one target creature. (A suspected creature has menace and can't block.)

Undercity Sewers

({T}: Add {U} or {B}.)
This land enters tapped.
When this land enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Swamp

Coerced to Kill

Enchant creature
You control enchanted creature.
Enchanted creature has base power and toughness 1/1, has deathtouch, and is an Assassin in addition to its other types.

Repeat Offender

{2}{B}: If this creature is suspected, put a +1/+1 counter on it. Otherwise, suspect it. (A suspected creature has menace and can't block.)

Curious Cadaver

Flying
When you sacrifice a Clue, return this card from your graveyard to your hand.