Repeal

Return target nonland permanent with mana value X to its owner's hand.
Draw a card.

Compulsive Research

Target player draws three cards. Then that player discards two cards unless they discard a land card.

Act of Treason

Gain control of target creature until end of turn. Untap that creature. It gains haste until end of turn. (It can attack and {T} this turn.)

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Sinister Sabotage

Counter target spell.
Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Island

Mountain

Burning Prophet

Whenever you cast a noncreature spell, Burning Prophet gets +1/+0 until end of turn, then scry 1.

Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Dogpile

Dogpile deals damage to any target equal to the number of attacking creatures you control.

Downsize

Target creature you don't control gets -4/-0 until end of turn.
Overload {2}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Izzet Charm

Choose one —
• Counter target noncreature spell unless its controller pays {2}.
• Izzet Charm deals 2 damage to target creature.
• Draw two cards, then discard two cards.

Izzet Guildgate

Izzet Guildgate enters the battlefield tapped.
{T}: Add {U} or {R}.

Muddle the Mixture

Counter target instant or sorcery spell.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Mugging

Mugging deals 2 damage to target creature. That creature can't block this turn.

Radical Idea

Draw a card.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)