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.)

Dusk Mangler

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

Goldhound

First strike
Menace (This creature can't be blocked except by two or more creatures.)
{T}, Sacrifice Goldhound: Add one mana of any color.

Raffine's Silencer

When Raffine's Silencer enters, it connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)
When Raffine's Silencer dies, target creature an opponent controls gets -X/-X until end of turn, where X is Raffine's Silencer's power.

Faerie Vandal

Flash (You may cast this spell any time you could cast an instant.)
Flying
Whenever you draw your second card each turn, put a +1/+1 counter on Faerie Vandal.

Syndicate Infiltrator

Flying
As long as there are five or more mana values among cards in your graveyard, Syndicate Infiltrator gets +2/+2.

Light 'Em Up

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.)
Light 'Em Up deals 2 damage to target creature or planeswalker.

Vampire Scrivener

Flying
Whenever you gain life during your turn, put a +1/+1 counter on Vampire Scrivener.
Whenever you lose life during your turn, put a +1/+1 counter on Vampire Scrivener.

Rumor Gatherer

Alliance — Whenever another creature you control enters, scry 1. If this is the second time this ability has resolved this turn, draw a card instead.

Night Clubber

When Night Clubber enters, creatures your opponents control get -1/-1 until end of turn.
Blitz {2}{B} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Celebrity Fencer

Alliance — Whenever another creature you control enters, put a +1/+1 counter on Celebrity Fencer.

Forge Boss

Whenever you sacrifice one or more other creatures, Forge Boss deals 2 damage to each opponent. This ability triggers only once each turn.

Wingshield Agent

Wingshield Agent enters with a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)
Whenever Wingshield Agent attacks, up to one other target creature gains flying until end of turn.

Unlucky Witness

When Unlucky Witness dies, exile the top two cards of your library. Until your next end step, you may play one of those cards.

Mayhem Patrol

Menace (This creature can't be blocked except by two or more creatures.)
Whenever Mayhem Patrol attacks, target creature gets +1/+0 until end of turn.
Blitz {1}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Inspiring Overseer

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

Pugnacious Pugilist

Whenever Pugnacious Pugilist attacks, create a tapped and attacking 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target."
Blitz {3}{R} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Jewel Thief

Vigilance, trample
When Jewel Thief enters, create a Treasure token. (It's an artifact with "{T}, Sacrifice this artifact: Add one mana of any color.")

Riveteers Decoy

Riveteers Decoy must be blocked if able.
Blitz {3}{G} (If you cast this spell for its blitz cost, it gains haste and "When this creature dies, draw a card." Sacrifice it at the beginning of the next end step.)

Tainted Indulgence

Draw two cards. Then discard a card unless there are five or more mana values among cards in your graveyard.