Consider

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

Wee Dragonauts

Flying
Whenever you cast an instant or sorcery spell, Wee Dragonauts gets +2/+0 until end of turn.

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Wavebreak Hippocamp

Whenever you cast your first spell during each opponent's turn, draw a card.

Sulfur Falls

Sulfur Falls enters tapped unless you control an Island or a Mountain.
{T}: Add {U} or {R}.

Visions of Beyond

Draw a card. If a graveyard has twenty or more cards in it, draw three cards instead.

Goblin Electromancer

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

Solve the Equation

Search your library for an instant or sorcery card, reveal it, put it into your hand, then shuffle.

Rapid Hybridization

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

Talisman of Creativity

{T}: Add {C}.
{T}: Add {U} or {R}. Talisman of Creativity deals 1 damage to you.

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

Silundi Isle

Silundi Isle enters tapped.
{T}: Add {U}.

Silundi Vision

Look at the top six cards of your library. You may reveal an instant or sorcery card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Silundi Vision // Silundi Isle

Blasphemous Act

This spell costs {1} less to cast for each creature on the battlefield.
Blasphemous Act deals 13 damage to each creature.

Ovika, Enigma Goliath

Flying
Ward—{3}, Pay 3 life.
Whenever you cast a noncreature spell, create X 1/1 red Phyrexian Goblin creature tokens, where X is the mana value of that spell. They gain haste until end of turn.

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.

Gitaxian Probe

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

Izzet Boilerworks

Izzet Boilerworks enters tapped.
When Izzet Boilerworks enters, return a land you control to its owner's hand.
{T}: Add {U}{R}.

Archmage Emeritus

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

Pongify

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

Exotic Orchard

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

Sprite Dragon

Flying, haste
Whenever you cast a noncreature spell, put a +1/+1 counter on Sprite Dragon.

Kraum, Ludevic's Opus

Flying, haste
Whenever an opponent casts their second spell each turn, draw a card.
Partner (You can have two commanders if both have partner.)

Crimson Wisps

Target creature becomes red and gains haste until end of turn. (It can attack and {T} this turn.)
Draw a card.

Sokenzan, Crucible of Defiance

{T}: Add {R}.
Channel — {3}{R}, Discard Sokenzan, Crucible of Defiance: Create two 1/1 colorless Spirit creature tokens. They gain haste until end of turn. This ability costs {1} less to activate for each legendary creature you control.

Mind Stone

{T}: Add {C}.
{1}, {T}, Sacrifice Mind Stone: Draw a card.

Past in Flames

Each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.
Flashback {4}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Arcane Signet

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

Jori En, Ruin Diver

Whenever you cast your second spell each turn, draw a card.

Otawara, Soaring City

{T}: Add {U}.
Channel — {3}{U}, Discard Otawara, Soaring City: Return target artifact, creature, enchantment, or planeswalker to its owner's hand. This ability costs {1} less to activate for each legendary creature you control.

Serum Visions

Peek

Look at target player's hand.
Draw a card.

Stormchaser Mage

Flying, haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)

Consecrated Sphinx

Flying
Whenever an opponent draws a card, you may draw two cards.

Sol Ring

Mountain

Ponder

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

Command Tower

Storm-Kiln Artist

Storm-Kiln Artist gets +1/+0 for each artifact you control.
Magecraft — Whenever you cast or copy an instant or sorcery spell, create a Treasure token.

Training Center

Training Center enters tapped unless you have two or more opponents.
{T}: Add {U} or {R}.

Quicken

The next sorcery spell you cast this turn can be cast as though it had flash. (It can be cast any time you could cast an instant.)
Draw a card.

Temple of Epiphany

This land enters tapped.
When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.)
{T}: Add {U} or {R}.

Thought Vessel

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

Steam Vents

({T}: Add {U} or {R}.)
As Steam Vents enters, you may pay 2 life. If you don't, it enters tapped.

Mystic Retrieval

Return target instant or sorcery card from your graveyard to your hand.
Flashback {2}{R} (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Talrand, Sky Summoner

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

Wizards of Thay

Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token copy that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Instant and sorcery spells you cast cost {1} less to cast.
You may cast sorcery spells as though they had flash.

Murmuring Mystic

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

Sleight of Hand

Look at the top two cards of your library. Put one of them into your hand and the other on the bottom of your library.

Metallurgic Summonings

Whenever you cast an instant or sorcery spell, create an X/X colorless Construct artifact creature token, where X is that spell's mana value.
{3}{U}{U}, Exile Metallurgic Summonings: Return all instant and sorcery cards from your graveyard to your hand. Activate only if you control six or more artifacts.

Wild Magic Surge

Destroy target permanent an opponent controls. Its controller reveals cards from the top of their library until they reveal a permanent card that shares a card type with that permanent. They put that card onto the battlefield and the rest on the bottom of their library in a random order.

Izzet Signet

Treasure Cruise

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

Primal Wellspring

(Transforms from Primal Amulet.)
{T}: Add one mana of any color. When that mana is spent to cast an instant or sorcery spell, copy that spell and you may choose new targets for the copy.

Primal Amulet

Instant and sorcery spells you cast cost {1} less to cast.
Whenever you cast an instant or sorcery spell, put a charge counter on Primal Amulet. Then if there are four or more charge counters on it, you may remove those counters and transform it.

Primal Amulet // Primal Wellspring

Sky Diamond

Shark Typhoon

Whenever you cast a noncreature spell, create an X/X blue Shark creature token with flying, where X is that spell's mana value.
Cycling {X}{1}{U} ({X}{1}{U}, Discard this card: Draw a card.)
When you cycle Shark Typhoon, create an X/X blue Shark creature token with flying.

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.)

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.)

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.

Chain Reaction

Chain Reaction deals X damage to each creature, where X is the number of creatures on the battlefield.

Expressive Iteration

Look at the top three cards of your library. Put one of them into your hand, put one of them on the bottom of your library, and exile one of them. You may play the exiled card this turn.

Brainstorm

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

An Offer You Can't Refuse

Counter target noncreature spell. Its controller creates two Treasure tokens. (They're artifacts with "{T}, Sacrifice this token: Add one mana of any color.")

Reflecting Pool

{T}: Add one mana of any type that a land you control could produce.

Resculpt

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

Sea Gate, Reborn

As Sea Gate, Reborn enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {U}.

Sea Gate Restoration

Draw cards equal to the number of cards in your hand plus one. You have no maximum hand size for the rest of the game.

Sea Gate Restoration // Sea Gate, Reborn

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.

Crackling Drake

Flying
Crackling Drake's power is equal to the total number of instant and sorcery cards you own in exile and in your graveyard.
When Crackling Drake enters, draw a card.

Narset's Reversal

Copy target instant or sorcery spell, then return it to its owner's hand. You may choose new targets for the copy.

Stormcarved Coast

Stormcarved Coast enters tapped unless you control two or more other lands.
{T}: Add {U} or {R}.

Spirebluff Canal

Spirebluff Canal enters tapped unless you control two or fewer other lands.
{T}: Add {U} or {R}.

Ludevic, Necro-Alchemist

At the beginning of each player's end step, that player may draw a card if a player other than you lost life this turn.
Partner (You can have two commanders if both have partner.)

Frostboil Snarl

As Frostboil Snarl enters, you may reveal an Island or Mountain card from your hand. If you don't, Frostboil Snarl enters tapped.
{T}: Add {U} or {R}.

Shivan Reef

{T}: Add {C}.
{T}: Add {U} or {R}. Shivan Reef deals 1 damage to you.

Murktide Regent

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Flying
Murktide Regent enters with a +1/+1 counter on it for each instant and sorcery card exiled with it.
Whenever an instant or sorcery card leaves your graveyard, put a +1/+1 counter on Murktide Regent.

Third Path Iconoclast

Whenever you cast a noncreature spell, create a 1/1 colorless Soldier artifact creature token.

Fire Diamond

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

Haughty Djinn

Flying
Haughty Djinn's power is equal to the number of instant and sorcery cards in your graveyard.
Instant and sorcery spells you cast cost {1} less to cast.

Cascade Bluffs

{T}: Add {C}.
{U/R}, {T}: Add {U}{U}, {U}{R}, or {R}{R}.

Expedite

Target creature gains haste until end of turn.
Draw a card.

Octavia, Living Thesis

This spell costs {8} less to cast if you have eight or more instant and/or sorcery cards in your graveyard.
Ward {8}
Magecraft — Whenever you cast or copy an instant or sorcery spell, target creature has base power and toughness 8/8 until end of turn.

Mystical Tutor

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

Young Pyromancer

Whenever you cast an instant or sorcery spell, create a 1/1 red Elemental creature token.

Counterspell

Counterflux

This spell can't be countered.
Counter target spell you don't control.
Overload {1}{U}{U}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

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.

Island

Negate

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Mizzix's Mastery

Exile target card that's an instant or sorcery from your graveyard. For each card exiled this way, copy it, and you may cast the copy without paying its mana cost. Exile Mizzix's Mastery.
Overload {5}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Twisted Image

Switch target creature's power and toughness until end of turn.
Draw a card.

Fiery Islet

{T}, Pay 1 life: Add {U} or {R}.
{1}, {T}, Sacrifice Fiery Islet: Draw a card.

Thought Scour

Target player mills two cards.
Draw a card.

Shatterskull, the Hammer Pass

As Shatterskull, the Hammer Pass enters, you may pay 3 life. If you don't, it enters tapped.
{T}: Add {R}.

Shatterskull Smashing

Shatterskull Smashing deals X damage divided as you choose among up to two target creatures and/or planeswalkers. If X is 6 or more, Shatterskull Smashing deals twice X damage divided as you choose among them instead.

Shatterskull Smashing // Shatterskull, the Hammer Pass

Dig Through Time

Delve (Each card you exile from your graveyard while casting this spell pays for {1}.)
Look at the top seven cards of your library. Put two of them into your hand and the rest on the bottom of your library in any order.

Keep Safe

Counter target spell that targets a permanent you control.
Draw a card.

Balmor, Battlemage Captain

Flying
Whenever you cast an instant or sorcery spell, creatures you control get +1/+0 and gain trample until end of turn.

Fellwar Stone

Gale, Waterdeep Prodigy

Whenever you cast an instant or sorcery spell from your hand, you may cast up to one target card of the other type from your graveyard. If a spell cast from your graveyard this way would be put into your graveyard, exile it instead.
Choose a Background (You can have a Background as a second commander.)