Rakdos Trumpeter

Menace (This creature can't be blocked except by two or more creatures.)
{3}{R}: This creature gets +2/+0 until end of turn.

Spawn of Mayhem

Spectacle {1}{B}{B} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Flying, trample
At the beginning of your upkeep, this creature deals 1 damage to each player. Then if you have 10 or less life, put a +1/+1 counter on this creature.

Spire Mangler

Flash
Flying
When this creature enters, target creature you control with flying gets +2/+0 until end of turn.

Thirsting Shade

Lifelink
{2}{B}: This creature gets +1/+1 until end of turn.

Undercity Scavenger

When this creature enters, you may sacrifice another creature. If you do, put two +1/+1 counters on this creature, then scry 2.

Undercity's Embrace

Target opponent sacrifices a creature of their choice. If you control a creature with power 4 or greater, you gain 4 life.

Forbidding Spirit

When this creature enters, until your next turn, creatures can't attack you or planeswalkers you control unless their controller pays {2} for each of those creatures.

Vindictive Vampire

Whenever another creature you control dies, this creature deals 1 damage to each opponent and you gain 1 life.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Amplifire

At the beginning of your upkeep, reveal cards from the top of your library until you reveal a creature card. Until your next turn, this creature's base power becomes twice that card's power and its base toughness becomes twice that card's toughness. Put the revealed cards on the bottom of your library in a random order.

Burn Bright

Creatures you control get +2/+0 until end of turn.

Burning-Tree Vandal

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever this creature attacks, you may discard a card. If you do, draw a card.

Cavalcade of Calamity

Whenever a creature you control with power 1 or less attacks, this enchantment deals 1 damage to the player or planeswalker that creature is attacking.

Clamor Shaman

Riot (This creature enters with your choice of a +1/+1 counter or haste.)
Whenever this creature attacks, target creature an opponent controls can't block this turn.

Dagger Caster

When this creature enters, it deals 1 damage to each opponent and 1 damage to each creature your opponents control.

Deface

Choose one —
• Destroy target artifact.
• Destroy target creature with defender.

Ravnica Allegiance