Core Set 2020 Theme Booster Red has variants:
Explore this pack in Sealed.

Sheets

Sheet uncommon (duplicates allowed)

At rate 2/29 (6.9%)
Chandra's Spitfire
Chandra, Novice Pyromancer
Dragon Mage
Ember Hauler
Flame Sweep
Fry
Goblin Ringleader
Mask of Immolation
Rapacious Dragon
Scampering Scorcher
Uncaged Fury
Unchained Berserker
At rate 1/58 (1.72%)
Colossus Hammer
Cryptic Caves
Diamond Knight
Diviner's Lockbox
Manifold Key
Meteor Golem
Pattern Matcher
Retributive Wand
Salvager of Ruin
Scuttlemutt

Sheet common (duplicates allowed)

At rate 4/83 (4.82%)
Act of Treason
Chandra's Embercat
Chandra's Outrage
Daggersail Aeronaut
Destructive Digger
Fire Elemental
Goblin Bird-Grabber
Goblin Smuggler
Infuriate
Keldon Raider
Lavakin Brawler
Maniacal Rage
Pack Mastiff
Reckless Air Strike
Reduce to Ashes
Ripscale Predator
Scorch Spitter
Shock
Tectonic Rift
At rate 1/83 (1.2%)
Anvilwrought Raptor
Evolving Wilds
Heart-Piercer Bow
Marauder's Axe
Prismite
Stone Golem
Vial of Dragonfire

Sheet rare_mythic

At rate 4/43 (9.3%)
Chandra's Regulator
Chandra, Acolyte of Flame
Drakuseth, Maw of Flames
Glint-Horn Buccaneer
Leyline of Combustion
Marauding Raptor
Repeated Reverberation
Thunderkin Awakener
At rate 2/43 (4.65%)
Cavalier of Flame
Chandra, Awakened Inferno
At rate 1/43 (2.33%)
Bag of Holding
Field of the Dead
Grafdigger's Cage
Icon of Ancestry
Lotus Field
Mystic Forge
Steel Overseer