Consider

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

Artificer's Epiphany

Draw two cards. If you control no artifacts, discard a card.

Mind Stone

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

Dragonstorm

Search your library for a Dragon permanent card, put it onto the battlefield, then shuffle.
Storm (When you cast this spell, copy it for each spell cast before it this turn.)

Snap

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

Volcanic Island

Prismari Command

Choose two —
• Prismari Command deals 2 damage to any target.
• Target player draws two cards, then discards two cards.
• Target player creates a Treasure token.
• Destroy target artifact.

Izzet Signet

Blasphemous Act

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

Rewind

Counter target spell. Untap up to four lands.

Ancestral Vision

Suspend 4—{U} (Rather than cast this card from your hand, pay {U} and exile it with four time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost.)
Target player draws three cards.

Boomerang

Return target permanent to its owner's hand.

Counterspell

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.)

Unstable Obelisk

{T}: Add {C}.
{7}, {T}, Sacrifice Unstable Obelisk: Destroy target permanent.

Steam Vents

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

Sol Ring

Arcane Signet

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

Electrolyze

Electrolyze deals 2 damage divided as you choose among one or two targets.
Draw a card.

Exalted Flamer of Tzeentch

Sorcerous Inspiration — At the beginning of your upkeep, return an instant or sorcery card at random from your graveyard to your hand.
Fire of Tzeentch — Whenever you cast an instant or sorcery spell, Exalted Flamer of Tzeentch deals 1 damage to each opponent.

Electrostatic Field

Defender
Whenever you cast an instant or sorcery spell, Electrostatic Field deals 1 damage to each opponent.

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.)

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.

Cryptic Command

Choose two —
• Counter target spell.
• Return target permanent to its owner's hand.
• Tap all creatures your opponents control.
• Draw a card.

Unwind

Counter target noncreature spell. Untap up to three lands.

Mountain

Pongify

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

Command Tower

Pyretic Ritual

Terramorphic Expanse

{T}, Sacrifice Terramorphic Expanse: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Lava Dart

Lava Dart deals 1 damage to any target.
Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Disallow

Counter target spell, activated ability, or triggered ability. (Mana abilities can't be targeted.)

Thermo-Alchemist

Defender
{T}: Thermo-Alchemist deals 1 damage to each opponent.
Whenever you cast an instant or sorcery spell, untap Thermo-Alchemist.

Frantic Search

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

Devastation Tide

Return all nonland permanents to their owners' hands.
Miracle {1}{U} (You may cast this card for its miracle cost when you draw it if it's the first card you drew this turn.)

Gelectrode

{T}: Gelectrode deals 1 damage to any target.
Whenever you cast an instant or sorcery spell, you may untap Gelectrode.

Brainstorm

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

Lantern of the Lost

When Lantern of the Lost enters, exile target card from a graveyard.
{1}, {T}, Exile Lantern of the Lost: Exile all cards from all graveyards, then draw a card.

Wasteland

{T}: Add {C}.
{T}, Sacrifice Wasteland: Destroy target nonbasic land.

Shower of Sparks

Shower of Sparks deals 1 damage to target creature and 1 damage to target player or planeswalker.

Fiery Islet

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

Thought Vessel

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

Niv-Mizzet, the Firemind

Flying
Whenever you draw a card, Niv-Mizzet, the Firemind deals 1 damage to any target.
{T}: 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.

Archmage's Charm

Choose one —
• Counter target spell.
• Target player draws two cards.
• Gain control of target nonland permanent with mana value 1 or less.

Chandra's Pyrohelix

Chandra's Pyrohelix deals 2 damage divided as you choose among one or two targets.

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}.

Seething Song

Gilded Lotus

Stormcarved Coast

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

Exotic Orchard

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

Training Center

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

Ghyrson Starn, Kelermorph

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
Three Autostubs — Whenever another source you control deals exactly 1 damage to a permanent or player, Ghyrson Starn, Kelermorph deals 2 damage to that permanent or player.

Forked Bolt

Forked Bolt deals 2 damage divided as you choose among one or two targets.

Twin Bolt

Twin Bolt deals 2 damage divided as you choose among one or two targets.

Kessig Flamebreather

Whenever you cast a noncreature spell, Kessig Flamebreather deals 1 damage to each opponent.

Rapid Hybridization

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

Relic of Progenitus

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

Sulfur Falls

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

Island

Pull from Tomorrow

Catalog

Commander's Sphere

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

You Find the Villains' Lair

Choose one —
• Foil Their Scheme — Counter target spell.
• Learn Their Secrets — Draw two cards, then discard two cards.

Ponder

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

Spirebluff Canal

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

Bane's Contingency

Counter target spell. If that spell targets a commander you control, instead counter that spell, scry 2, then draw a card.

Fire

Fire deals 2 damage divided as you choose among one or two targets.

Fire // Ice

Needle Drop

Needle Drop deals 1 damage to any target that was dealt damage this turn.
Draw a card.

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.

Izzet Cluestone

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

Backdraft Hellkite

Flying
Whenever Backdraft Hellkite attacks, each instant and sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.

Izzet Keyrune

{T}: Add {U} or {R}.
{U}{R}: Until end of turn, Izzet Keyrune becomes a 2/1 blue and red Elemental artifact creature.
Whenever Izzet Keyrune deals combat damage to a player, you may draw a card. If you do, discard a card.

Firebrand Archer

Whenever you cast a noncreature spell, this creature deals 1 damage to each opponent.

Gut Shot

({R/P} can be paid with either {R} or 2 life.)
Gut Shot deals 1 damage to any target.

Visions of Beyond

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

Niv-Mizzet, Parun

This spell can't be countered.
Flying
Whenever you draw a card, Niv-Mizzet, Parun deals 1 damage to any target.
Whenever a player casts an instant or sorcery spell, you draw a card.

Keep Safe

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

Rockslide Sorcerer

Whenever you cast an instant, sorcery, or Wizard spell, Rockslide Sorcerer deals 1 damage to any target.