Unexpected Windfall

As an additional cost to cast this spell, discard a card.
Draw two cards and create two Treasure tokens. (They're artifacts with "{T}, Sacrifice this artifact: Add one mana of any color.")

Island

Screaming Fury

Target creature gets +5/+0 and gains haste until end of turn.

Mana Leak

Counter target spell unless its controller pays {3}.

Brainstorm

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

Commander's Sphere

{T}: Add one mana of any color in your commander's color identity.
Sacrifice Commander's Sphere: Draw a card.

Faithless Looting

Draw two cards, then discard two cards.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Compulsive Research

Target player draws three cards. Then that player discards two cards unless they discard a land card.

Counterspell

Unsummon

Return target creature to its owner's hand.

Cancel

Negate

Izzet Guildgate

This land enters tapped.
{T}: Add {U} or {R}.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Mountain

Artful Dodge

Target creature can't be blocked this turn.
Flashback {U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Dispel

Nivix Cyclops

Defender
Whenever you cast an instant or sorcery spell, Nivix Cyclops gets +3/+0 until end of turn and can attack this turn as though it didn't have defender.

Spellheart Chimera

Flying, trample
Spellheart Chimera's power is equal to the number of instant and sorcery cards in your graveyard.

Sea Gate

Sea Gate enters tapped.
As Sea Gate enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Miscalculation

Counter target spell unless its controller pays {2}.
Cycling {2} ({2}, Discard this card: Draw a card.)

Fling

As an additional cost to cast this spell, sacrifice a creature.
Fling deals damage equal to the sacrificed creature's power to any target.

Wistful Thinking

Target player draws two cards, then discards four cards.

Strategic Planning

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.

Force Spike

Counter target spell unless its controller pays {1}.

Crimson Wisps

Target creature becomes red and gains haste until end of turn. (It can attack and {T} this turn.)
Draw a card.

Glint

Target creature you control gets +0/+3 and gains hexproof until end of turn. (It can't be the target of spells or abilities your opponents control.)

Thriving Bluff

Thriving Bluff enters tapped. As it enters, choose a color other than red.
{T}: Add {R} or one mana of the chosen color.

Confound

Counter target spell that targets a creature.
Draw a card.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Expedite

Target creature gains haste until end of turn.
Draw a card.

Mizzium Skin

Target creature you control gets +0/+1 and gains hexproof until end of turn.
Overload {1}{U} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Ponder

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

Thriving Isle

Thriving Isle enters tapped. As it enters, choose a color other than blue.
{T}: Add {U} or one mana of the chosen color.

Goblin Electromancer

Instant and sorcery spells you cast cost {1} less to cast.

Psychotic Fury

Target multicolored creature gains double strike until end of turn.
Draw a card.

Assault Strobe

Target creature gains double strike until end of turn. (It deals both first-strike and regular combat damage.)