
Counterflux | Instant | | This spell can't be countered.
Counter target spell you don't control.
Overload {1}{U}{U}{R} (You may cast this spell for its overload cost. If you do, change its text by replacing all instances of "target" with "each.") | Scott M. Fischer

Firemind's Foresight | Instant | | Search your library for an instant card with mana value 3, reveal it, and put it into your hand. Then repeat this process for instant cards with mana values 2 and 1. Then shuffle. | Dan Scott

Hypersonic Dragon | Creature | Dragon | Flying, haste
You may cast sorcery spells as though they had flash. (You may cast them any time you could cast an instant.) | Dan Scott

Mercurial Chemister | Creature | Human Wizard | {U}, {T}: Draw two cards.
{R}, {T}, Discard a card: Mercurial Chemister deals damage to target creature equal to the discarded card's mana value. | Wesley Burt

Nivmagus Elemental | Creature | Elemental | Exile an instant or sorcery spell you control: Put two +1/+1 counters on Nivmagus Elemental. (That spell won't resolve.) | Mike Bierek

Carnival Hellsteed | Creature | Nightmare Horse | First strike, haste
Unleash (You may have this creature enter the battlefield with a +1/+1 counter on it. It can't block as long as it has a +1/+1 counter on it.) | Chase Stone

Dreadbore | Sorcery | | Destroy target creature or planeswalker. | Wayne Reynolds

Havoc Festival | Enchantment | | Players can't gain life.
At the beginning of each player's upkeep, that player loses half their life, rounded up. | Johannes Voss

Slaughter Games | Sorcery | | This spell can't be countered.
Choose a nonland card name. Search target opponent's graveyard, hand, and library for any number of cards with that name and exile them. Then that player shuffles. | Steve Prescott

Cryptborn Horror | Creature | Horror | Trample
Cryptborn Horror enters the battlefield with X +1/+1 counters on it, where X is the total life lost by your opponents this turn. | Richard Wright