Consider

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

Contaminated Aquifer

({T}: Add {U} or {B}.)
This land enters tapped.

Cryptic Serpent

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

Steel Sabotage

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

Thought Scour

Target player mills two cards.
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.)

Spell Pierce

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

Echoing Truth

Return target nonland permanent and all other permanents with the same name as that permanent to their owners' hands.

Island

Murmuring Mystic

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

Tormod's Crypt

{T}, Sacrifice this artifact: Exile target player's graveyard.

Counterspell

Sleep of the Dead

Tap target creature. It doesn't untap during its controller's next untap step.
Escape—{2}{U}, Exile three other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

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}.)

Swamp

Dispel

Dreams of Laguna

Surveil 1, then draw a card. (To surveil 1, look at the top card of your library. You may put it into your graveyard.)
Flashback {3}{U} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Annul

Counter target artifact or enchantment spell.

Soaring Seacliff

This land enters tapped.
When this land enters, target creature gains flying until end of turn.
{T}: Add {U}.

Brainstorm

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

Resentful Revelation

Look at the top three cards of your library. Put one of them into your hand and the rest into your graveyard.
Flashback {6}{B} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Snap

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

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.)

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 this creature.

Delver of Secrets // Insectile Aberration

Shinra Reinforcements

When this creature enters, mill three cards and you gain 3 life. (To mill three cards, put the top three cards of your library into your graveyard.)