Consider

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

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

Rewind

Counter target spell. Untap up to four lands.

Sol Ring

Counterspell

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.

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.)

Arcane Signet

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

Baral, Chief of Compliance

Instant and sorcery spells you cast cost {1} less to cast.
Whenever a spell or ability you control counters a spell, you may draw a card. If you do, discard a card.

Talrand, Sky Summoner

Whenever you cast an instant or sorcery spell, create a 2/2 blue Drake creature token with flying.

Reality Shift

Exile target creature. Its controller manifests the top card of their library. (That player puts the top card of their library onto the battlefield face down as a 2/2 creature. If it's a creature card, it can be turned face up any time for its mana cost.)

Frantic Search

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

Archmage Emeritus

Magecraft — Whenever you cast or copy an instant or sorcery spell, draw a card.

Gitaxian Probe

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

High Tide

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

Aetherize

Return all attacking creatures to their owner's hand.

Brainstorm

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

Pongify

Destroy target creature. It can't be regenerated. Its controller creates a 3/3 green Ape creature token.

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

Murmuring Mystic

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

Impulse

Look at the top four cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Negate

Zephyr Scribe

{U}, {T}: Draw a card, then discard a card.
Whenever you cast a noncreature spell, untap Zephyr Scribe.

Jace's Sanctum

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, scry 1.

Thought Vessel

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.)

Telepathy

Your opponents play with their hands revealed.

Heraldic Banner

As this artifact enters, choose a color.
Creatures you control of the chosen color get +1/+0.
{T}: Add one mana of the chosen color.

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.

Treasure Cruise

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

Anticipate

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order.

Divination

Ponder

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

Font of Fortunes

{1}{U}, Sacrifice Font of Fortunes: Draw two cards.

Rapid Hybridization

Destroy target creature. It can't be regenerated. That creature's controller creates a 3/3 green Frog Lizard creature token.