Mystical Dispute

This spell costs {2} less to cast if it targets a blue spell.
Counter target spell unless its controller pays {3}.

Ashiok, Dream Render

Spells and abilities your opponents control can't cause their controller to search their library.
−1: Target player mills four cards. Then exile each opponent's graveyard.

Consider

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

Sleight of Hand

Look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Temporal Trespass

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Take an extra turn after this one. Exile Temporal Trespass.

Hall of Storm Giants

If you control two or more other lands, Hall of Storm Giants enters tapped.
{T}: Add {U}.
{5}{U}: Until end of turn, Hall of Storm Giants becomes a 7/7 blue Giant creature with ward {3}. It's still a land. (Whenever it becomes the target of a spell or ability an opponent controls, counter it unless that player pays {3}.)

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Thundering Falls

({T}: Add {U} or {R}.)
Thundering Falls enters tapped.
When Thundering Falls enters, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Island

Treasure Cruise

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Draw three cards.

Negate

Galvanic Iteration

When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
Flashback {1}{U}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Spirebluff Canal

Spirebluff Canal enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {R}.

Prismari Command

Choose two —
• Prismari Command deals 2 damage to any target.
• Target player draws two cards, then discards two cards.
• Target player creates a Treasure token.
• Destroy target artifact.

Ledger Shredder

Flying
Whenever a player casts their second spell each turn, Ledger Shredder connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Crackling Drake

Flying
Crackling Drake's power is equal to the total number of instant and sorcery cards you own in exile and in your graveyard.
When Crackling Drake enters, draw a card.

Tears of Valakut

This spell can't be countered.
Tears of Valakut deals 5 damage to target creature with flying.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Spell Pierce

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

Arclight Phoenix

Flying, haste
At the beginning of combat on your turn, if you've cast three or more instant and sorcery spells this turn, return Arclight Phoenix from your graveyard to the battlefield.

Fiery Impulse

Fiery Impulse deals 2 damage to target creature.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, Fiery Impulse deals 3 damage instead.

Petty Theft

Return target nonland permanent an opponent controls to its owner's hand.

Brazen Borrower

Flash
Flying
Brazen Borrower can block only creatures with flying.

Brazen Borrower // Petty Theft

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

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Sweltering Suns

Sweltering Suns deals 3 damage to each creature.
Cycling {3} ({3}, Discard this card: Draw a card.)

Free the Fae

Mill four cards. Then put an instant, sorcery, or Faerie card from among the milled cards into your hand.