
Chaos Imps | Creature | Imp | Flying
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.)
Chaos Imps has trample as long as it has a +1/+1 counter on it. | Tyler Jacobson

Explosive Impact | Instant | | Explosive Impact deals 5 damage to any target. | Steve Argyle

Guild Feud | Enchantment | | At the beginning of your upkeep, target opponent reveals the top three cards of their library, may put a creature card from among them onto the battlefield, then puts the rest into their graveyard. You do the same with the top three cards of your library. If two creatures are put onto the battlefield this way, those creatures fight each other. | Karl Kopinski

Tenement Crasher | Creature | Beast | Haste | Warren Mahy

Niv-Mizzet, Dracogenius | Legendary Creature | Dragon Wizard | Flying
Whenever Niv-Mizzet, Dracogenius deals damage to a player, you may draw a card.
{U}{R}: Niv-Mizzet, Dracogenius deals 1 damage to any target. | Todd Lockwood

Carnival Hellsteed | Creature | Nightmare Horse | First strike, haste
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.) | Chase Stone

Havoc Festival | Enchantment | | Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up. | Johannes Voss

Rakdos Ringleader | Creature | Skeleton Warrior | First strike
Whenever Rakdos Ringleader deals combat damage to a player, that player discards a card at random.
{B}: Regenerate Rakdos Ringleader. | Jason Felix