Dispel

Dispersal Shield

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

Gainsay

Annul

Counter target artifact or enchantment spell.

Gitaxian Probe

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

Disdainful Stroke

Counter target spell with mana value 4 or greater.

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

Deprive

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

Hard Evidence

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

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.

Turn Aside

Counter target spell that targets a permanent you control.

Mishra's Factory

{T}: Add {C}.
{1}: This land 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.

Rapid Hybridization

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

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.

Consider

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

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.

Nullify

Ponder

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

Intervene

Counter target spell that targets a creature.

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.

Outwit

Counter target spell that targets a player.

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.

Island

Envelop

Flashfreeze

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.