45 cards where the text includes “would deal damage” and the color identity ≤ R

Dark Sphere (The Dark #100)
Dual Doomsuits (Unstable #179)
Desperate Gambit (Weatherlight #96)
Lava Burst (Masters Edition II #134)
Quest for Pure Flame (Zendikar #144)
Shield of the Avatar (Magic 2015 #230)
Don't Try This at Home (Unfinity #105)
Shield of the Realm (Dominaria #228)
The Flame of Keld (Dominaria #123)
General's Regalia (Mercadian Masques #295)
Invasion of Regatha // Disciples of the Inferno (March of the Machine #148)
Invasion of Regatha // Disciples of the Inferno (March of the Machine #148)
Mechanized Warfare (The Brothers' War #139)
Pyromancer's Swath (Modern Masters #125)
Akki Lavarunner // Tok-Tok, Volcano Born (Champions of Kamigawa #153)
Bone Mask (Mirage #295)
Calamity Bearer (Kaldheim #125)
Furnace of Rath (Planechase #55)
Goblin Bowling Team (Unglued #44)
Goldnight Castigator (Shadows over Innistrad #162)
Jade Monolith (Masters Edition IV #208)
Nova Pentacle (Masters Edition III #200)
Overblaze (Betrayers of Kamigawa #114)
Pentagram of the Ages (Masters Edition IV #220)
Sulfuric Vapors (Urza's Saga #220)
Torbran, Thane of Red Fell (Throne of Eldraine #147)
Bitter Feud (Commander Anthology Volume II #84)
Curse of Bloodletting (Dark Ascension #85)
Dictate of the Twin Gods (Journey into Nyx #93)
Embermaw Hellion (Magic Origins #141)
Fire Servant (Magic 2011 #137)
Gratuitous Violence (Forgotten Realms Commander #127)
Isengard Unleashed (Tales of Middle-earth Commander #495)
Jaya, Venerated Firemage (War of the Spark #135)
Orbs of Warding (Magic Origins #234)
Pyromancer's Gauntlet (Magic 2014 #214)
The Countdown Is at One (Unstable #80)
Uncivil Unrest (March of the Machine Commander #35)
Fiendish Duo (Murders at Karlov Manor Commander #153)
Fiery Emancipation (Core Set 2021 #143)
Goblin Goliath (Game Night #4)
Hostility (Commander Anthology Volume II #105)
Insult // Injury (Amonkhet #213)
Urza's Armor (Eighth Edition #318)
Angrath's Marauders (Outlaws of Thunder Junction Commander #153)
City on Fire (March of the Machine #135)

The message was clear to Sorin—time to search for something else.