Electrolyze

Electrolyze deals 2 damage divided as you choose among one or two targets.
Draw a card.

Counterspell

Mana Leak

Counter target spell unless its controller pays {3}.

Zealous Conscripts

Haste
When Zealous Conscripts enters, gain control of target permanent until end of turn. Untap that permanent. It gains haste until end of turn.

Mountain

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Pestermite

Flash
Flying
When Pestermite enters, you may tap or untap target permanent.

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

Deceiver Exarch

Flash (You may cast this spell any time you could cast an instant.)
When Deceiver Exarch enters, choose one —
• Untap target permanent you control.
• Tap target permanent an opponent controls.

Kiki-Jiki, Mirror Breaker

Haste
{T}: Create a token that's a copy of target nonlegendary creature you control, except it has haste. Sacrifice it at the beginning of the next end step.

Scry 1. (Look at the top card of your library. You may put that card on the bottom.)
Draw a card.