36 cards where the card is tagged “second-spell-matters”

Bloodsky Berserker (Kaldheim #80)
Breeches, the Blastmaker (Outlaws of Thunder Junction #197)
Brimstone Roundup (Outlaws of Thunder Junction #115)
Clarion Spirit (Kaldheim #6)
Codespell Cleric (Kaldheim #7)
Doomskar Oracle (Kaldheim #10)
Dreamtide Whale (Modern Horizons 3 #59)
Edgin, Larcenous Lutenist (Secret Lair Drop #1242)
Elmar, Ulvenwald Informant (Universes Within #4)
Eris, Roar of the Storm (Outlaws of Thunder Junction Commander #5)
Firja, Judge of Valor (Kaldheim #209)
Goldbug, Humanity's Ally // Goldbug, Scrappy Scout (Transformers #11)
Goldbug, Humanity's Ally // Goldbug, Scrappy Scout (Transformers #11)
Incursion Specialist (Gatecrash #38)
Infernal Pet (Kaldheim #99)
Iron-Fist Pulverizer (Outlaws of Thunder Junction #131)
Jori En, Ruin Diver (Duel Decks: Mind vs. Might #23)
Kraum, Violent Cacophony (Outlaws of Thunder Junction #214)
Lavinia, Foil to Conspiracy (Ravnica: Clue Edition #36)
Ledger Shredder (Streets of New Capenna #46)
Loan Shark (Outlaws of Thunder Junction #55)
Malcolm, the Eyes (Outlaws of Thunder Junction #219)
Monk Class (Adventures in the Forgotten Realms #228)
Monk of the Open Hand (Adventures in the Forgotten Realms #25)
Oji, the Exquisite Blade (Commander Legends: Battle for Baldur's Gate #290)
Pyromancer's Assault (Oath of the Gatewatch #115)
Raging Battle Mouse (Wilds of Eldraine #143)
Rammas Echor, Ancient Shield (Tales of Middle-earth Commander #505)
Razzle-Dazzler (Outlaws of Thunder Junction #63)
Sapphire Collector (Alchemy: Outlaws of Thunder Junction #13)
Shackle Slinger (Outlaws of Thunder Junction #65)
Slick Sequence (Outlaws of Thunder Junction #233)
Stella Lee, Wild Card (Outlaws of Thunder Junction Commander #3)
The Council of Four (Commander Legends: Battle for Baldur's Gate #271)
Thunder Drake (Ravnica: Clue Edition #102)
Tomb of Horrors Adventurer (Commander Legends: Battle for Baldur's Gate #100)
Xerex Strobe-Knight (March of the Machine #85)

Though this query has ended, its relics still slumber in New Argive.