Fireblast

You may sacrifice two Mountains rather than pay this spell's mana cost.
Fireblast deals 4 damage to any target.

Prismatic Vista

{T}, Pay 1 life, Sacrifice Prismatic Vista: Search your library for a basic land card, put it onto the battlefield, then shuffle.

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.

Arcane Signet

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

Underworld Breach

Each nonland card in your graveyard has escape. The escape cost is equal to the card's mana cost plus exile three other cards from your graveyard. (You may cast cards from your graveyard for their escape cost.)
At the beginning of the end step, sacrifice Underworld Breach.

Urza's Bauble

{T}, Sacrifice Urza's Bauble: Look at a card at random in target player's hand. You draw a card at the beginning of the next turn's upkeep.

Kessig Flamebreather

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

Grim Lavamancer

{R}, {T}, Exile two cards from your graveyard: Grim Lavamancer deals 2 damage to any target.

Chain Lightning

Chain Lightning deals 3 damage to any target. Then that player or that permanent's controller may pay {R}{R}. If the player does, they may copy this spell and may choose a new target for that copy.

True-Name Nemesis

As True-Name Nemesis enters, choose a player.
True-Name Nemesis has protection from the chosen player.

Ral, Storm Conduit

Whenever you cast or copy an instant or sorcery spell, Ral, Storm Conduit deals 1 damage to target opponent or planeswalker.
+2: Scry 1.
−2: When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.

Bedlam Reveler

This spell costs {1} less to cast for each instant and sorcery card in your graveyard.
Prowess
When Bedlam Reveler enters, discard your hand, then draw three cards.

Bloodstained Mire

{T}, Pay 1 life, Sacrifice Bloodstained Mire: Search your library for a Swamp or Mountain card, put it onto the battlefield, then shuffle.

Submerge

If an opponent controls a Forest and you control an Island, you may cast this spell without paying its mana cost.
Put target creature on top of its owner's library.

Talisman of Creativity

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

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}.

Dragon's Rage Channeler

Whenever you cast a noncreature spell, surveil 1. (Look at the top card of your library. You may put that card into your graveyard.)
Delirium — As long as there are four or more card types among cards in your graveyard, Dragon's Rage Channeler gets +2/+2, has flying, and attacks each combat if able.

Stormwing Entity

This spell costs {2}{U} less to cast if you've cast an instant or sorcery spell this turn.
Flying
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
When Stormwing Entity enters, scry 2.

Shrapnel Blast

As an additional cost to cast this spell, sacrifice an artifact.
Shrapnel Blast deals 5 damage to any target.

Young Pyromancer

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

Steam Vents

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

Ponder

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

Spell Pierce

Counter target noncreature spell unless its controller pays {2}.

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.

Molten Tributary

({T}: Add {U} or {R}.)
Molten Tributary enters tapped.

Fiery Islet

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

Soul-Scar Mage

Prowess
If a source you control would deal noncombat damage to a creature an opponent controls, put that many -1/-1 counters on that creature instead.

Vapor Snag

Return target creature to its owner's hand. Its controller loses 1 life.

Tale's End

Counter target activated ability, triggered ability, or legendary spell.

Negate

Mishra's Bauble

{T}, Sacrifice Mishra's Bauble: Look at the top card of target player's library. Draw a card at the beginning of the next turn's upkeep.

Arid Mesa

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

Aria of Flame

When Aria of Flame enters, each opponent gains 10 life.
Whenever you cast an instant or sorcery spell, put a verse counter on Aria of Flame, then it deals damage equal to the number of verse counters on it to target player or planeswalker.

Guttersnipe

Whenever you cast an instant or sorcery spell, Guttersnipe deals 2 damage to each opponent.

Conjurer's Bauble

{T}, Sacrifice Conjurer's Bauble: Put up to one target card from your graveyard on the bottom of your library. Draw a card.

Rift Bolt

Rift Bolt deals 3 damage to any target.
Suspend 1—{R} (Rather than cast this card from your hand, you may pay {R} and exile it with a time counter 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.)

Dreadhorde Arcanist

Trample
Whenever Dreadhorde Arcanist attacks, you may cast target instant or sorcery card with mana value less than or equal to Dreadhorde Arcanist's power from your graveyard without paying its mana cost. If that spell would be put into your graveyard, exile it instead.

Monastery Swiftspear

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

Electrostatic Field

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

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Will, Scholar of Frost

Instant and sorcery spells you cast cost {1} less to cast.
+1: Up to one target creature has base power and toughness 0/2 until your next turn.
−3: Draw two cards.
−7: Exile up to five target permanents. For each permanent exiled this way, its controller creates a 4/4 blue and red Elemental creature token.

Rowan, Scholar of Sparks

Instant and sorcery spells you cast cost {1} less to cast.
+1: Rowan, Scholar of Sparks deals 1 damage to each opponent. If you've drawn three or more cards this turn, she deals 3 damage to each opponent instead.
−4: You get an emblem with "Whenever you cast an instant or sorcery spell, you may pay {2}. If you do, copy that spell. You may choose new targets for the copy."

Rowan, Scholar of Sparks // Will, Scholar of Frost

Light Up the Stage

Spectacle {R} (You may cast this spell for its spectacle cost rather than its mana cost if an opponent lost life this turn.)
Exile the top two cards of your library. Until the end of your next turn, you may play those cards.

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.

Voltage Surge

As an additional cost to cast this spell, you may sacrifice an artifact.
Voltage Surge deals 2 damage to target creature or planeswalker. If this spell's additional cost was paid, Voltage Surge deals 4 damage instead.

Gitaxian Probe

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

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.)

Lava Spike

Lava Spike deals 3 damage to target player or planeswalker.

Cascade Bluffs

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

Stormchaser Mage

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

Insectile Aberration

Delver of Secrets

At the beginning of your upkeep, look at the top card of your library. You may reveal that card. If an instant or sorcery card is revealed this way, transform Delver of Secrets.

Delver of Secrets // Insectile Aberration

Firebrand Archer

Whenever you cast a noncreature spell, Firebrand Archer deals 1 damage to each opponent.

Mountain

Thermo-Alchemist

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

Island

Great Furnace

An Offer You Can't Refuse

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

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.

Brainstorm

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

Wooded Foothills

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

Sulfur Falls

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

Abrade

Choose one —
• Abrade deals 3 damage to target creature.
• Destroy target artifact.

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.

Demilich

This spell costs {U} less to cast for each instant and sorcery spell you've cast this turn.
Whenever Demilich attacks, exile up to one target instant or sorcery card from your graveyard. Copy it. You may cast the copy.
You may cast Demilich from your graveyard by exiling four instant and/or sorcery cards from your graveyard in addition to paying its other costs.

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.)