Blue Sun's Twilight

Gain control of target creature with mana value X or less. If X is 5 or more, create a token that's a copy of that creature.

Shaman's Trance

Other players can't play lands or cast spells from their graveyards this turn. You may play lands and cast spells from other players' graveyards this turn as though those cards were in your graveyard.

Piracy

Until end of turn, you may tap lands you don't control for mana. Spend this mana only to cast spells.

Mana Clash

You and target opponent each flip a coin. Mana Clash deals 1 damage to each player whose coin comes up tails. Repeat this process until both players' coins come up heads on the same flip.

Plagiarize

Until end of turn, if target player would draw a card, instead that player skips that draw and you draw a card.

Commandeer

You may exile two blue cards from your hand rather than pay this spell's mana cost.
Gain control of target noncreature spell. You may choose new targets for it. (If that spell is an artifact, enchantment, or planeswalker, the permanent enters under your control.)

Desertion

Counter target spell. If an artifact or creature spell is countered this way, put that card onto the battlefield under your control instead of into its owner's graveyard.

Sarkhan, Dragonsoul

+2: Sarkhan, Dragonsoul deals 1 damage to each opponent and each creature your opponents control.
−3: Sarkhan, Dragonsoul deals 4 damage to target player or planeswalker.
−9: Search your library for any number of Dragon creature cards, put them onto the battlefield, then shuffle.

Bribery

Search target opponent's library for a creature card and put that card onto the battlefield under your control. Then that player shuffles.

Game of Chaos

Flip a coin. If you win the flip, you gain 1 life and target opponent loses 1 life, and you decide whether to flip again. If you lose the flip, you lose 1 life and that opponent gains 1 life, and that player decides whether to flip again. Double the life stakes with each flip.

Spelljack

Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard. You may play it without paying its mana cost for as long as it remains exiled. (If it has X in its mana cost, X is 0.)

Thieves' Auction

Exile all nontoken permanents. Starting with you, each player chooses one of the exiled cards and puts it onto the battlefield tapped under their control. Repeat this process until all cards exiled this way have been chosen.

Mages' Contest

You and target spell's controller bid life. You start the bidding with a bid of 1. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid. If you win the bidding, counter that spell.

Mind Bomb

Each player may discard up to three cards. Mind Bomb deals damage to each player equal to 3 minus the number of cards they discarded this way.

Gather Specimens

If a creature would enter the battlefield under an opponent's control this turn, it enters under your control instead.

Illicit Auction

Each player may bid life for control of target creature. You start the bidding with a bid of 0. In turn order, each player may top the high bid. The bidding ends if the high bid stands. The high bidder loses life equal to the high bid and gains control of the creature. (This effect lasts indefinitely.)