War of the Spark

Ahn-Crop Invader | Creature | Zombie Minotaur Warrior | As long as it's your turn, Ahn-Crop Invader has first strike. {1}, Sacrifice another creature: Ahn-Crop Invader gets +2/+0 until end of turn. | Tomasz Jedruszek

Devouring Hellion | Creature | Hellion | As Devouring Hellion enters the battlefield, you may sacrifice any number of creatures and/or planeswalkers. If you do, it enters with twice that many +1/+1 counters on it. | Bayard Wu

Krenko, Tin Street Kingpin | Legendary Creature | Goblin | Whenever Krenko, Tin Street Kingpin attacks, put a +1/+1 counter on it, then create a number of 1/1 red Goblin creature tokens equal to Krenko's power. | Mark Behm

Raging Kronch | Creature | Beast | Raging Kronch can't attack alone. | Steve Prescott

Spellgorger Weird | Creature | Weird | Whenever you cast a noncreature spell, put a +1/+1 counter on Spellgorger Weird. | James Paick

Feather, the Redeemed | Legendary Creature | Angel | Flying Whenever you cast an instant or sorcery spell that targets a creature you control, exile that card instead of putting it into your graveyard as it resolves. If you do, return it to your hand at the beginning of the next end step. | Wayne Reynolds

Mayhem Devil | Creature | Devil | Whenever a player sacrifices a permanent, Mayhem Devil deals 1 damage to any target. | Dmitry Burmak

Living Twister | Creature | Elemental | {1}{R}, Discard a land card: Living Twister deals 2 damage to any target. {G}: Return a tapped land you control to its owner's hand. | James Paick

Rubblebelt Rioters | Creature | Human Berserker | Haste Whenever Rubblebelt Rioters attacks, it gets +X/+0 until end of turn, where X is the greatest power among creatures you control. | Tomasz Jedruszek