War of the Spark

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

Tibalt, Rakish Instigator | Legendary Planeswalker | Tibalt | Your opponents can't gain life. −2: Create a 1/1 red Devil creature token with "When this creature dies, it deals 1 damage to any target." | Chase Stone

Invade the City | Sorcery | | Amass X, where X is the number of instant and sorcery cards in your graveyard. (Put X +1/+1 counters on an Army you control. If you don't control one, create a 0/0 black Zombie Army creature token first.) | Sung Choi

Saheeli, Sublime Artificer | Legendary Planeswalker | Saheeli | Whenever you cast a noncreature spell, create a 1/1 colorless Servo artifact creature token. −2: Target artifact you control becomes a copy of another target artifact or creature you control until end of turn, except it's an artifact in addition to its other types. | Wesley Burt

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

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