Toxic Deluge

As an additional cost to cast this spell, pay X life.
All creatures get -X/-X until end of turn.

Deep Analysis

Target player draws two cards.
Flashback—{1}{U}, Pay 3 life. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Banefire

Banefire deals X damage to any target.
If X is 5 or more, this spell can't be countered and the damage can't be prevented.

Fireball

This spell costs {1} more to cast for each target beyond the first.
Fireball deals X damage divided evenly, rounded down, among any number of targets.

Chemister's Insight

Draw two cards.
Jump-start (You may cast this card from your graveyard by discarding a card in addition to paying its other costs. Then exile this card.)

Sol Ring

Rolling Thunder

Rolling Thunder deals X damage divided as you choose among any number of targets.

Conflagrate

Conflagrate deals X damage divided as you choose among any number of targets.
Flashback—{R}{R}, Discard X cards. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Torment of Hailfire

Repeat the following process X times. Each opponent loses 3 life unless that player sacrifices a nonland permanent of their choice or discards a card.

Black Sun's Zenith

Put X -1/-1 counters on each creature. Shuffle Black Sun's Zenith into its owner's library.

Cormela, Glamour Thief

Haste
{1}, {T}: Add {U}{B}{R}. Spend this mana only to cast instant and/or sorcery spells.
When Cormela, Glamour Thief dies, return up to one target instant or sorcery card from your graveyard to your hand.

Magmaquake

Magmaquake deals X damage to each creature without flying and each planeswalker.

Disintegrate

Disintegrate deals X damage to any target. If it's a creature, it can't be regenerated this turn, and if it would die this turn, exile it instead.

Izzet Signet

Pestilent Spirit

Menace, deathtouch
Instant and sorcery spells you control have deathtouch. (Any amount of damage they deal to a creature is enough to destroy it.)

Dimir Signet

Profane Command

Choose two —
• Target player loses X life.
• Return target creature card with mana value X or less from your graveyard to the battlefield.
• Target creature gets -X/-X until end of turn.
• Up to X target creatures gain fear until end of turn. (They can't be blocked except by artifact creatures and/or black creatures.)

Rakdos Signet

Pyromancer's Goggles

{T}: Add {R}. When that mana is spent to cast a red instant or sorcery spell, copy that spell and you may choose new targets for the copy.

Arcane Signet

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

Rolling Earthquake

Rolling Earthquake deals X damage to each creature without horsemanship and each player.

Maestros Charm

Choose one —
• Look at the top five cards of your library. Put one of those cards into your hand and the rest into your graveyard.
• Each opponent loses 3 life and you gain 3 life.
• Maestros Charm deals 5 damage to target creature or planeswalker.

Exsanguinate

Each opponent loses X life. You gain life equal to the life lost this way.

Crackle with Power

Crackle with Power deals five times X damage to each of up to X targets.

Trouble

Trouble deals damage to target player equal to the number of cards in that player's hand.
Fuse (You may cast one or both halves of this card from your hand.)

Toil

Target player draws two cards and loses 2 life.
Fuse (You may cast one or both halves of this card from your hand.)