Consider

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

Gush

You may return two Islands you control to their owner's hand rather than pay this spell's mana cost.
Draw two cards.

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Tormenting Voice

Arcane Signet

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

Rite of Flame

Add {R}{R}, then add {R} for each card named Rite of Flame in each graveyard.

Telling Time

Look at the top three cards of your library. Put one of those cards into your hand, one on top of your library, and one on the bottom of your library.

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.")

Sulfurous Blast

Sulfurous Blast deals 2 damage to each creature and each player. If you cast this spell during your main phase, Sulfurous Blast deals 3 damage to each creature and each player instead.

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.)

Firemind Vessel

Firemind Vessel enters tapped.
{T}: Add two mana of different colors.

Brainstorm

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

Muddle the Mixture

Counter target instant or sorcery spell.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Big Score

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.")

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.)

Arcane Denial

Counter target spell. Its controller may draw up to two cards at the beginning of the next turn's upkeep.
You draw a card at the beginning of the next turn's upkeep.

Star Compass

Star Compass enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Simian Spirit Guide

Exile Simian Spirit Guide from your hand: Add {R}.

Dizzy Spell

Target creature gets -3/-0 until end of turn.
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Ravenform

Exile target artifact or creature. Its controller creates a 1/1 blue Bird creature token with flying.
Foretell {U} (During your turn, you may pay {2} and exile this card from your hand face down. Cast it on a later turn for its foretell cost.)

Snap

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

Rewind

Counter target spell. Untap up to four lands.

Seething Song

Izzet Locket

{T}: Add {U} or {R}.
{U/R}{U/R}{U/R}{U/R}, {T}, Sacrifice Izzet Locket: Draw two cards.

Frantic Search

Draw two cards, then discard two cards. Untap up to three lands.

Robe of Mirrors

Enchant creature (Target a creature as you cast this. This card enters attached to that creature.)
Enchanted creature has shroud. (It can't be the target of spells or abilities.)

Memory Lapse

Counter target spell. If that spell is countered this way, put it on top of its owner's library instead of into that player's graveyard.

Serum Visions

Stern Dismissal

Return target creature or enchantment an opponent controls to its owner's hand.

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

Resculpt

Exile target artifact or creature. Its controller creates a 4/4 blue and red Elemental creature token.

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Drift of Phantasms

Defender (This creature can't attack.)
Flying
Transmute {1}{U}{U} ({1}{U}{U}, Discard this card: Search your library for a card with the same mana value as this card, reveal it, put it into your hand, then shuffle. Transmute only as a sorcery.)

Unwind

Counter target noncreature spell. Untap up to three lands.

Mana Geyser

Add {R} for each tapped land your opponents control.

Pieces of the Puzzle

Reveal the top five cards of your library. Put up to two instant and/or sorcery cards from among them into your hand and the rest into your graveyard.

Mystic Sanctuary

({T}: Add {U}.)
Mystic Sanctuary enters tapped unless you control three or more other Islands.
When Mystic Sanctuary enters untapped, you may put target instant or sorcery card from your graveyard on top of your library.

Merchant Scroll

Search your library for a blue instant card, reveal that card, put it into your hand, then shuffle.

Meeting of Minds

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Draw two cards.

Rhystic Study

Whenever an opponent casts a spell, you may draw a card unless that player pays {1}.

Archaeomancer

When Archaeomancer enters, return target instant or sorcery card from your graveyard to your hand.

Goblin Electromancer

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

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Gitaxian Probe

({U/P} can be paid with either {U} or 2 life.)
Look at target player's hand.
Draw a card.

Fellwar Stone

{T}: Add one mana of any color that a land an opponent controls could produce.

Teach by Example

({U/R} can be paid with either {U} or {R}.)
When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Pirate's Pillage

Izzet Cluestone

{T}: Add {U} or {R}.
{U}{R}, {T}, Sacrifice Izzet Cluestone: Draw a card.

Commander's Sphere

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

Cathartic Reunion

As an additional cost to cast this spell, discard two cards.
Draw three cards.

Izzet Signet

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.)

Counterspell

Swirling Sandstorm

Threshold — Swirling Sandstorm deals 5 damage to each creature without flying if seven or more cards are in your graveyard.

Ponder

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

Negate

Wayfarer's Bauble

{2}, {T}, Sacrifice Wayfarer's Bauble: Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Sky Diamond

Grapeshot

Grapeshot deals 1 damage to any target.
Storm (When you cast this spell, copy it for each spell cast before it this turn. You may choose new targets for the copies.)

Pyretic Ritual

Dive Down

Meldweb Curator

When Meldweb Curator enters, put up to one target instant or sorcery card from your graveyard on top of your library.

Mountain

Island

Unexpected Windfall

Seize the Spoils

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

Energy Tap

Tap target untapped creature you control. If you do, add an amount of {C} equal to that creature's mana value.

Fire Diamond

Fire Diamond enters tapped.
{T}: Add {R}.

Treasure Cruise

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

Melek, Izzet Paragon

Play with the top card of your library revealed.
You may cast instant and sorcery spells from the top of your library.
Whenever you cast an instant or sorcery spell from your library, copy it. You may choose new targets for the copy.

Command Tower

Demand Answers

As an additional cost to cast this spell, sacrifice an artifact or discard a card.
Draw two cards.

Desperate Ritual

Add {R}{R}{R}.
Splice onto Arcane {1}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Mnemonic Wall

Defender
When Mnemonic Wall enters, you may return target instant or sorcery card from your graveyard to your hand.

High Tide

Until end of turn, whenever a player taps an Island for mana, that player adds an additional {U}.

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}.

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Bloodwater Entity

Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Bloodwater Entity enters, you may put target instant or sorcery card from your graveyard on top of your library.