Thought Scour

Target player mills two cards.
Draw a card.

Insectile Aberration

Delver of Secrets

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform Delver of Secrets.

Delver of Secrets // Insectile Aberration

Cryptic Serpent

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.

Blue Elemental Blast

Choose one —
• Counter target red spell.
• Destroy target red permanent.

Brainstorm

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

Hydroblast

Choose one —
• Counter target spell if it's red.
• Destroy target permanent if it's red.

Steel Sabotage

Choose one —
• Counter target artifact spell.
• Return target artifact to its owner's hand.

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Force Spike

Counter target spell unless its controller pays {1}.

Mental Note

Spell Pierce

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

Murmuring Mystic

Whenever you cast an instant or sorcery spell, create a 1/1 blue Bird Illusion creature token with flying.

Tolarian Terror

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)

Snap

Return target creature to its owner's hand. Untap up to two lands.

Counterspell

Consider

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

Lórien Revealed

Draw three cards.
Islandcycling {1} ({1}, Discard this card: Search your library for an Island card, reveal it, put it into your hand, then shuffle.)