Guilds of Ravnica

Electrostatic Field | Creature | Wall | Defender Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent. | Dan Scott

Goblin Cratermaker | Creature | Goblin Warrior | {1}, Sacrifice Goblin Cratermaker: Choose one — • Goblin Cratermaker deals 2 damage to target creature. • Destroy target colorless nonland permanent. | Svetlin Velinov

Lava Coil | Sorcery | | Lava Coil deals 4 damage to target creature. If that creature would die this turn, exile it instead. | Wesley Burt

Boros Challenger | Creature | Human Soldier | Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.) {2}{R}{W}: Boros Challenger gets +1/+1 until end of turn. | Gabor Szikszai

Justice Strike | Instant | | Target creature deals damage to itself equal to its power. | Clint Cearley

Legion Guildmage | Creature | Human Wizard | {5}{R}, {T}: Legion Guildmage deals 3 damage to each opponent. {2}{W}, {T}: Tap another target creature. | Zack Stella

Beamsplitter Mage | Creature | Vedalken Wizard | Whenever you cast an instant or sorcery spell that targets only Beamsplitter Mage, if you control one or more other creatures that spell could target, choose one of those creatures. Copy that spell. The copy targets the chosen creature. | Svetlin Velinov

League Guildmage | Creature | Human Wizard | {3}{U}, {T}: Draw a card. {X}{R}, {T}: Copy target instant or sorcery spell you control with mana value X. You may choose new targets for the copy. | Svetlin Velinov