Jori En, Ruin Diver

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

Calculated Dismissal

Counter target spell unless its controller pays {3}.
Spell mastery — If there are two or more instant and/or sorcery cards in your graveyard, scry 2. (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.)

Overwhelming Denial

Surge {U}{U} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
This spell can't be countered.
Counter target spell.

Fevered Visions

At the beginning of each player's end step, that player draws a card. If the player is your opponent and has four or more cards in hand, Fevered Visions deals 2 damage to that player.

Mountain

Stormchaser Mage

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

Fiery Temper

Fiery Temper deals 3 damage to any target.
Madness {R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)

Sphinx of the Final Word

This spell can't be countered.
Flying, hexproof
Instant and sorcery spells you control can't be countered.

Boulder Salvo

Surge {1}{R} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Boulder Salvo deals 4 damage to target creature.

Fall of the Titans

Surge {X}{R} (You may cast this spell for its surge cost if you or a teammate has cast another spell this turn.)
Fall of the Titans deals X damage to each of up to two targets.

Island

Pyromancer's Assault

Whenever you cast your second spell each turn, Pyromancer's Assault deals 2 damage to any target.

Confirm Suspicions

Counter target spell.
Investigate three times. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Prism Ring

As Prism Ring enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Avacyn's Judgment

Madness {X}{R} (If you discard this card, discard it into exile. When you do, cast it for its madness cost or put it into your graveyard.)
Avacyn's Judgment deals 2 damage divided as you choose among any number of targets. If this spell's madness cost was paid, it deals X damage divided as you choose among those permanents and/or players instead.

Weaver of Lightning

Reach
Whenever you cast an instant or sorcery spell, Weaver of Lightning deals 1 damage to target creature an opponent controls.

Mercurial Geists

Flying
Whenever you cast an instant or sorcery spell, Mercurial Geists gets +3/+0 until end of turn.

Jace, Unraveler of Secrets

+1: Scry 1, then draw a card.
−2: Return target creature to its owner's hand.
−8: You get an emblem with "Whenever an opponent casts their first spell each turn, counter that spell."

Awoken Horror

When this creature transforms into Awoken Horror, return all non-Horror creatures to their owners' hands.

Thing in the Ice

Defender
Thing in the Ice enters with four ice counters on it.
Whenever you cast an instant or sorcery spell, remove an ice counter from Thing in the Ice. Then if it has no ice counters on it, transform it.

Thing in the Ice // Awoken Horror

Thermo-Alchemist

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

Highland Lake

Highland Lake enters tapped.
{T}: Add {U} or {R}.

Harness the Storm

Whenever you cast an instant or sorcery spell from your hand, you may cast target card with the same name as that spell from your graveyard. (You still pay its costs.)

Persistent Nightmare

Skulk (This creature can't be blocked by creatures with greater power.)
When Persistent Nightmare deals combat damage to a player, return it to its owner's hand.

Startled Awake

Target opponent mills thirteen cards.
{3}{U}{U}: Put Startled Awake from your graveyard onto the battlefield transformed. Activate only as a sorcery.

Startled Awake // Persistent Nightmare

Twin Bolt

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

Lightning Axe

As an additional cost to cast this spell, discard a card or pay {5}.
Lightning Axe deals 5 damage to target creature.

Encase in Ice

Flash (You may cast this spell any time you could cast an instant.)
Enchant red or green creature
When Encase in Ice enters, tap enchanted creature.
Enchanted creature doesn't untap during its controller's untap step.

Geistblast

Geistblast deals 2 damage to any target.
{2}{U}, Exile Geistblast from your graveyard: Copy target instant or sorcery spell you control. You may choose new targets for the copy.

Nivix Barrier

Flash (You may cast this spell any time you could cast an instant.)
Defender (This creature can't attack.)
When Nivix Barrier enters, target attacking creature gets -4/-0 until end of turn.