19 cards where the card is tagged “synergy-color-choose”

Caged Sun (Commander Anthology Volume II #178)
Diamond Knight (Core Set 2020 #224)
Diamond Mare (Core Set 2019 #231)
Gauntlet of Power (Dominaria Remastered #223)
Hall of Triumph (Journey into Nyx #162)
Heraldic Banner (Throne of Eldraine #222)
Jeweled Torque (Mercadian Masques #301)
Lurebound Scarecrow (Shadowmoor #256)
Nykthos, Shrine to Nyx (Theros #223)
Nyx (March of the Machine Commander #61)
Nyx Lotus (Theros Beyond Death #235)
Paradise Plume (Commander 2021 #255)
Prism Ring (Magic Origins #235)
Rith, the Awakener (Dominaria Remastered #198)
Seal of the Guildpact (Ravnica Remastered #266)
Tablet of the Guilds (Return to Ravnica #235)
The Prismatic Piper (Commander Masters #1)
Throne of Eldraine (Wilds of Eldraine Commander #28)
Treva, the Renewer (Duel Decks: Phyrexia vs. the Coalition #49)

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