Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Blight Grenade

Destroy target creature.
All creatures get -3/-3 until end of turn.

Cateran Summons

Search your library for a Mercenary card, reveal that card, put it into your hand, then shuffle.

Abandon Hope

As an additional cost to cast this spell, discard X cards.
Look at target opponent's hand and choose X cards from it. That player discards those cards.

Cruel Entertainment

Choose target player and another target player. The first player controls the second player during the second player's next turn, and the second player controls the first player during the first player's next turn.

Back in Town

Return X target outlaw creature cards from your graveyard to the battlefield. (Assassins, Mercenaries, Pirates, Rogues, and Warlocks are outlaws.)

Crippling Fear

Choose a creature type. Creatures that aren't of the chosen type get -3/-3 until end of turn.

Battle at the Bridge

Improvise (Your artifacts can help cast this spell. Each artifact you tap after you're done activating mana abilities pays for {1}.)
Target creature gets -X/-X until end of turn. You gain X life.

Crumbling Ashes

At the beginning of your upkeep, destroy target creature with a -1/-1 counter on it.