Getting

Impatience

At the beginning of each player's end step, if that player didn't cast a spell this turn, Impatience deals 2 damage to that player.

Star Compass

Star Compass enters tapped.
{T}: Add one mana of any color that a basic land you control could produce.

Ancient Runes

At the beginning of each player's upkeep, Ancient Runes deals damage to that player equal to the number of artifacts they control.

Harsh Mentor

Whenever an opponent activates an ability of an artifact, creature, or land on the battlefield, if it isn't a mana ability, Harsh Mentor deals 2 damage to that player.

Mikokoro, Center of the Sea

{T}: Add {C}.
{2}, {T}: Each player draws a card.

Have

Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Don't Have

Citadel of Pain

At the beginning of each player's end step, Citadel of Pain deals X damage to that player, where X is the number of untapped lands they control.

The Flame of Keld

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Discard your hand.
II — Draw two cards.
III — If a red source you control would deal damage to a permanent or player this turn, it deals that much damage plus 2 to that permanent or player instead.

Angrath's Marauders

If a source you control would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Comet Storm

Multikicker {1} (You may pay an additional {1} any number of times as you cast this spell.)
Choose any target, then choose another target for each time this spell was kicked. Comet Storm deals X damage to each of them.

Mechanized Warfare

If a red or artifact source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 1 instead.

Smash to Smithereens

Destroy target artifact. Smash to Smithereens deals 3 damage to that artifact's controller.

Scorch Spitter

Whenever Scorch Spitter attacks, it deals 1 damage to the player or planeswalker it's attacking.

Flame Rift

Flame Rift deals 4 damage to each player.

Prodigal Pyromancer

{T}: Prodigal Pyromancer deals 1 damage to any target.

Planar Atlas

Planar Atlas enters tapped.
When Planar Atlas enters, you may look at the top four cards of your library. If you do, reveal up to one land card from among them, then put that card on top of your library and the rest on the bottom in a random order.
{T}: Add {C}.

Pyroclasm

Pyroclasm deals 2 damage to each creature.

Torbran, Thane of Red Fell

If a red source you control would deal damage to an opponent or a permanent an opponent controls, it deals that much damage plus 2 instead.

Lobber Crew

Defender
{T}: Lobber Crew deals 1 damage to each opponent.
Whenever you cast a multicolored spell, untap Lobber Crew.

Furnace of Rath

If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Jaya, Venerated Firemage

If another red source you control would deal damage to a permanent or player, it deals that much damage plus 1 to that permanent or player instead.
−2: Jaya, Venerated Firemage deals 2 damage to any target.

Firebrand Archer

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

Sulfuric Vapors

If a red spell would deal damage to a permanent or player, it deals that much damage plus 1 to that permanent or player instead.

Foriysian Totem

{T}: Add {R}.
{4}{R}: Foriysian Totem becomes a 4/4 red Giant artifact creature with trample until end of turn.
As long as Foriysian Totem is a creature, it can block an additional creature each combat.

End the Festivities

End the Festivities deals 1 damage to each opponent and each creature and planeswalker they control.

Kris Mage

{R}, {T}, Discard a card: Kris Mage deals 1 damage to any target.

Mizzium Mortars

Mizzium Mortars deals 4 damage to target creature you don't control.
Overload {3}{R}{R}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.")

Anger of the Gods

Anger of the Gods deals 3 damage to each creature. If a creature dealt damage this way would die this turn, exile it instead.

Sol Ring

Hour of Devastation

All creatures lose indestructible until end of turn. Hour of Devastation deals 5 damage to each creature and each non-Bolas planeswalker.

Dismissive Pyromancer

{R}, {T}, Discard a card: Draw a card.
{2}{R}, {T}, Sacrifice Dismissive Pyromancer: It deals 4 damage to target creature.

Mountain

Welder Automaton

{3}{R}: Welder Automaton deals 1 damage to each opponent.

Commander's Sphere

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

Solphim, Mayhem Dominus

If a source you control would deal noncombat damage to an opponent or a permanent an opponent controls, it deals double that damage to that player or permanent instead.
{1}{R/P}{R/P}, Discard two cards: Put an indestructible counter on Solphim, Mayhem Dominus. ({R/P} can be paid with either {R} or 2 life.)

Embermaw Hellion

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
If another red source you control would deal damage to a permanent or player, it deals that much damage plus 1 to that permanent or player instead.

Fire Diamond

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

Volcanic Fallout

This spell can't be countered.
Volcanic Fallout deals 2 damage to each creature and each player.

Thermo-Alchemist

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

Fireslinger

{T}: Fireslinger deals 1 damage to any target and 1 damage to you.

Scalding Devil

{2}{R}: Scalding Devil deals 1 damage to target player or planeswalker.

Prismatic Lens

{T}: Add {C}.
{1}, {T}: Add one mana of any color.

Blasphemous Act

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

Shock

Chandra's Magmutt

{T}: Chandra's Magmutt deals 1 damage to target player or planeswalker.

Spear Spewer

Defender
{T}: Spear Spewer deals 1 damage to each player.

Chain Reaction

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

Mogg Fanatic

Sacrifice Mogg Fanatic: It deals 1 damage to any target.

Burning Earth

Whenever a player taps a nonbasic land for mana, Burning Earth deals 1 damage to that player.

Obsidian Fireheart

{1}{R}{R}: Put a blaze counter on target land without a blaze counter on it. For as long as that land has a blaze counter on it, it has "At the beginning of your upkeep, this land deals 1 damage to you." (The land continues to burn after Obsidian Fireheart has left the battlefield.)

Ghirapur Orrery

Each player may play an additional land on each of their turns.
At the beginning of each player's upkeep, if that player has no cards in hand, that player draws three cards.

Blisterspit Gremlin

{1}, {T}: Blisterspit Gremlin deals 1 damage to each opponent.
Whenever you cast a noncreature spell, untap Blisterspit Gremlin.

Conspiracy Theorist

Whenever Conspiracy Theorist attacks, you may pay {1} and discard a card. If you do, draw a card.
Whenever you discard one or more nonland cards, you may exile one of them from your graveyard. If you do, you may cast it this turn.

Slagstorm

Choose one —
• Slagstorm deals 3 damage to each creature.
• Slagstorm deals 3 damage to each player.

Magus of the Wheel

{1}{R}, {T}, Sacrifice Magus of the Wheel: Each player discards their hand, then draws seven cards.

Arcane Signet

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

Goblin Fireslinger

{T}: Goblin Fireslinger deals 1 damage to target player or planeswalker.

Careless Celebrant

When Careless Celebrant dies, it deals 2 damage to target creature or planeswalker an opponent controls.

Sulfuric Vortex

At the beginning of each player's upkeep, Sulfuric Vortex deals 2 damage to that player.
If a player would gain life, that player gains no life instead.

Dictate of the Twin Gods

Flash
If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Manabarbs

Whenever a player taps a land for mana, Manabarbs deals 1 damage to that player.

Cinder Pyromancer

{T}: Cinder Pyromancer deals 1 damage to target player or planeswalker.
Whenever you cast a red spell, you may untap Cinder Pyromancer.

Roiling Vortex

At the beginning of each player's upkeep, Roiling Vortex deals 1 damage to them.
Whenever a player casts a spell, if no mana was spent to cast that spell, Roiling Vortex deals 5 damage to that player.
{R}: Your opponents can't gain life this turn.

Mind Stone

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

Viashino Heretic

{1}{R}, {T}: Destroy target artifact. Viashino Heretic deals damage to that artifact's controller equal to the artifact's mana value.

Letter of Acceptance

{T}: Add one mana of any color.
{2}, {T}, Sacrifice Letter of Acceptance: Draw a card.