Guilds of Ravnica

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

Conclave Guildmage | Creature | Elf Cleric | {G}, {T}: Creatures you control gain trample until end of turn. {5}{W}, {T}: Create a 2/2 green and white Elf Knight creature token with vigilance. | Jason Rainville

Worldsoul Colossus | Creature | Elemental | Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.) Worldsoul Colossus enters the battlefield with X +1/+1 counters on it. | James Paick

Dimir Spybug | Creature | Insect | Flying Menace (This creature can't be blocked except by two or more creatures.) Whenever you surveil, put a +1/+1 counter on Dimir Spybug. | James Paick

House Guildmage | Creature | Human Wizard | {1}{U}, {T}: Target creature doesn't untap during its controller's next untap step. {2}{B}, {T}: Surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.) | Winona Nelson

Thought Erasure | Sorcery | | Target opponent reveals their hand. You choose a nonland card from it. That player discards that card. Surveil 1. (Look at the top card of your library. You may put it into your graveyard.) | Anna Steinbauer

Discovery | Sorcery | | Surveil 2, then draw a card. (To surveil 2, look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.) | Mark Behm

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

Glowspore Shaman | Creature | Elf Shaman | When Glowspore Shaman enters the battlefield, mill three cards. You may put a land card from your graveyard on top of your library. | Lars Grant-West

Swarm Guildmage | Creature | Elf Shaman | {4}{B}, {T}: Creatures you control get +1/+0 and gain menace until end of turn. (They can't be blocked except by two or more creatures.) {1}{G}, {T}: You gain 2 life. | Simon Dominic