Deal Gone Bad

Target creature gets -3/-3 until end of turn. Target player mills three cards. (They put the top three cards of their library into their graveyard.)

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Inspiring Overseer

Flying
When this creature enters, you gain 1 life and draw a card.

Boon of Safety

Put a shield counter on target creature. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
Scry 1.

Shattered Seraph

Flying
When this creature enters, you gain 3 life.
{2}, Exile this card from your hand: Target land gains "{T}: Add {W}, {U}, or {B}" until this card is cast from exile. You may cast this card for as long as it remains exiled.

Rooftop Nuisance

Casualty 1 (As you cast this spell, you may sacrifice a creature with power 1 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Tap target creature. It doesn't untap during its controller's next untap step.
Draw a card.

Cut of the Profits

Casualty 3 (As you cast this spell, you may sacrifice a creature with power 3 or greater. When you do, copy this spell.)
You draw X cards and you lose X life.

Snooping Newsie

When this creature enters, mill two cards. (Put the top two cards of your library into your graveyard.)
As long as there are five or more mana values among cards in your graveyard, this creature gets +1/+1 and has lifelink.

Plains

Maestros Initiate

{4}{U/R}, Exile this card from your graveyard: Draw two cards, then discard a card.

Cut Your Losses

Casualty 2 (As you cast this spell, you may sacrifice a creature with power 2 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Target player mills half their library, rounded down.

Echo Inspector

Flying
When this creature enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Demon's Due

Scry 2, then draw two cards. You lose 2 life.

Maestros Theater

When this land enters, sacrifice it. When you do, search your library for a basic Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Undercover Operative

You may have this creature enter as a copy of any creature on the battlefield, except it enters with a shield counter on it if you control that creature. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

Murder

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Dusk Mangler

As an additional cost to cast this spell, sacrifice a creature, discard a card, or pay 4 life.
When this creature enters, each opponent sacrifices a creature of their choice, discards a card, and loses 4 life.

Raffine's Informant

When this creature enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Backstreet Bruiser

Defender
As long as there are two or more counters among creatures you control, this creature can attack as though it didn't have defender.

Psychic Pickpocket

When this creature enters, it connives. When it connives this way, return up to one target nonland permanent to its owner's hand. (To have a creature connive, draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on that creature.)

Make Disappear

Casualty 1 (As you cast this spell, you may sacrifice a creature with power 1 or greater. When you do, copy this spell and you may choose a new target for the copy.)
Counter target spell unless its controller pays {2}.

Sleep with the Fishes

Enchant creature
When this Aura enters, tap enchanted creature and you create a 1/1 blue Fish creature token with "This token can't be blocked."
Enchanted creature doesn't untap during its controller's untap step.

Psionic Snoop

Flash
When this creature enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Island

Waterfront District

This land enters tapped.
{T}: Add {U} or {B}.
{2}{U}{B}, {T}, Sacrifice this land: Draw a card.

Crooked Custodian

Security Bypass

Enchant creature
As long as enchanted creature is attacking alone, it can't be blocked.
Enchanted creature has "Whenever this creature deals combat damage to a player, it connives." (Its controller draws a card, then discards a card. If they discarded a nonland card, they put a +1/+1 counter on this creature.)

Raffine's Guidance

Enchant creature
Enchanted creature gets +1/+1.
You may cast this card from your graveyard by paying {2}{W} rather than paying its mana cost.

Cutthroat Contender

Pay 1 life: This creature gets +1/+0 until end of turn. Activate only once each turn.

Revel Ruiner

Menace (This creature can't be blocked except by two or more creatures.)
When this creature enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Swamp

Expendable Lackey

{1}{U}, Exile this card from your graveyard: Create a 1/1 blue Fish creature token with "This token can't be blocked." Activate only as a sorcery.

Backup Agent

When this creature enters, put a +1/+1 counter on target creature.

Rogues' Gallery

For each color, return up to one target creature card of that color from your graveyard to your hand.