
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

Steam Vents | Land | Island Mountain | ({T}: Add {U} or {R}.)
As Steam Vents enters the battlefield, you may pay 2 life. If you don't, it enters the battlefield tapped. | Yeong-Hao Han