Consider

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

Daze

You may return an Island you control to its owner's hand rather than pay this spell's mana cost.
Counter target spell unless its controller pays {1}.

Cabal Ritual

Add {B}{B}{B}.
Threshold — Add {B}{B}{B}{B}{B} instead if seven or more cards are in your graveyard.

Brainstorm

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

Lion's Eye Diamond

Discard your hand, Sacrifice Lion's Eye Diamond: Add three mana of any one color. Activate only as an instant.

Relic of Progenitus

{T}: Target player exiles a card from their graveyard.
{1}, Exile Relic of Progenitus: Exile all graveyards. Draw a card.

Ponder

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

Unmask

You may exile a black card from your hand rather than pay this spell's mana cost.
Target player reveals their hand. You choose a nonland card from it. That player discards that card.

Street Wraith

Swampwalk (This creature can't be blocked as long as defending player controls a Swamp.)
Cycling—Pay 2 life. (Pay 2 life, Discard this card: Draw a card.)

Misty Rainforest

{T}, Pay 1 life, Sacrifice Misty Rainforest: Search your library for a Forest or Island card, put it onto the battlefield, then shuffle.

Duress

Target opponent reveals their hand. You choose a noncreature, nonland card from it. That player discards that card.

Personal Tutor

Search your library for a sorcery card, reveal it, then shuffle and put that card on top.

Grief

Menace
When Grief enters, target opponent reveals their hand. You choose a nonland card from it. That player discards that card.
Evoke—Exile a black card from your hand.

Lotus Petal

{T}, Sacrifice Lotus Petal: Add one mana of any color.

Underground Sea

Chain of Vapor

Return target nonland permanent to its owner's hand. Then that permanent's controller may sacrifice a land. If the player does, they may copy this spell and may choose a new target for that copy.

Collective Brutality

Escalate—Discard a card. (Pay this cost for each mode chosen beyond the first.)
Choose one or more —
• Target opponent reveals their hand. You choose an instant or sorcery card from it. That player discards that card.
• Target creature gets -2/-2 until end of turn.
• Target opponent loses 2 life and you gain 2 life.

Scalding Tarn

{T}, Pay 1 life, Sacrifice Scalding Tarn: Search your library for an Island or Mountain card, put it onto the battlefield, then shuffle.

Doomsday

Search your library and graveyard for five cards and exile the rest. Put the chosen cards on top of your library in any order. You lose half your life, rounded up.

Polluted Delta

{T}, Pay 1 life, Sacrifice Polluted Delta: Search your library for an Island or Swamp card, put it onto the battlefield, then shuffle.

Force of Negation

If it's not your turn, you may exile a blue card from your hand rather than pay this spell's mana cost.
Counter target noncreature spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard.

Flusterstorm

Counter target instant or sorcery spell unless its controller pays {1}.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Force of Will

You may pay 1 life and exile a blue card from your hand rather than pay this spell's mana cost.
Counter target spell.

Edge of Autumn

If you control four or fewer lands, search your library for a basic land card, put it onto the battlefield tapped, then shuffle.
Cycling—Sacrifice a land. (Sacrifice a land, Discard this card: Draw a card.)

Mystical Dispute

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

Snow-Covered Island

Flooded Strand

{T}, Pay 1 life, Sacrifice Flooded Strand: Search your library for a Plains or Island card, put it onto the battlefield, then shuffle.

Dark Ritual

Thassa's Oracle

When Thassa's Oracle enters, look at the top X cards of your library, where X is your devotion to blue. Put up to one of them on top of your library and the rest on the bottom of your library in a random order. If X is greater than or equal to the number of cards in your library, you win the game. (Each {U} in the mana costs of permanents you control counts toward your devotion to blue.)

Leyline of the Void

If Leyline of the Void is in your opening hand, you may begin the game with it on the battlefield.
If a card would be put into an opponent's graveyard from anywhere, exile it instead.

Cavern of Souls

As Cavern of Souls enters, choose a creature type.
{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a creature spell of the chosen type, and that spell can't be countered.

Thoughtseize

Target player reveals their hand. You choose a nonland card from it. That player discards that card. You lose 2 life.