Outwit

Counter target spell that targets a player.

Flashfreeze

Intervene

Counter target spell that targets a creature.

Disdainful Stroke

Counter target spell with mana value 4 or greater.

Stubborn Denial

Counter target noncreature spell unless its controller pays {1}.
Ferocious — If you control a creature with power 4 or greater, counter that spell instead.

Test of Talents

Counter target instant or sorcery spell. Search its controller's graveyard, hand, and library for any number of cards with the same name as that spell and exile them. That player shuffles, then draws a card for each card exiled from their hand this way.

Annul

Counter target artifact or enchantment spell.

Deprive

As an additional cost to cast this spell, return a land you control to its owner's hand.
Counter target spell.

Consider

Surveil 1. (Look at the top card of your library. You may put it into your graveyard.)
Draw a card.

Dispersal Shield

Counter target spell if its mana value is less than or equal to the highest mana value among permanents you control.

Polymorph

Destroy target creature. It can't be regenerated. Its controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield, then shuffles all other cards revealed this way into their library.

Dispel

Proteus Staff

{2}{U}, {T}: Put target creature on the bottom of its owner's library. That creature's controller reveals cards from the top of their library until they reveal a creature card. The player puts that card onto the battlefield and the rest on the bottom of their library in any order. Activate only as a sorcery.

Turn Aside

Counter target spell that targets a permanent you control.

Gainsay

Detection Tower

{T}: Add {C}.
{1}, {T}: Until end of turn, your opponents and creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.

Counter target spell if no mana was spent to cast it.

Hard Evidence

Create a 0/3 blue Crab creature token.
Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Island

Nullify

Ponder

Look at the top three cards of your library, then put them back in any order. You may shuffle.
Draw a card.

Mishra's Factory

{T}: Add {C}.
{1}: Mishra's Factory becomes a 2/2 Assembly-Worker artifact creature until end of turn. It's still a land.
{T}: Target Assembly-Worker creature gets +1/+1 until end of turn.

Brainstorm

Draw three cards, then put two cards from your hand on top of your library in any order.

Tidespout Tyrant

Flying
Whenever you cast a spell, return target permanent to its owner's hand.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.