40 cards where the mana produced is UW

Azorius Chancery (Ravnica: Clue Edition #229)
Azorius Cluestone (Dragon's Maze #136)
Azorius Guildgate (Ravnica: Clue Edition #230)
Azorius Keyrune (Commander Anthology #209)
Azorius Locket (Crimson Vow Commander #160)
Azorius Signet (Ravnica: Clue Edition #219)
Boreal Shelf (Coldsnap #144)
Celestial Colonnade (Ultimate Masters #238)
Coastal Tower (Duel Decks: Mirrodin Pure vs. New Phyrexia #38)
Deserted Beach (Innistrad: Midnight Hunt #260)
Fieldmist Borderpost (Archenemy #85)
Fortified Beachhead (The Brothers' War #262)
Glacial Floodplain (Kaldheim #257)
Glacial Fortress (Ixalan #255)
Hallowed Fountain (Ravnica Remastered #280)
Hengegate Pathway // Mistgate Pathway (Kaldheim #260)
Hengegate Pathway // Mistgate Pathway (Kaldheim #260)
Idyllic Beachfront (Dominaria United #249)
Irrigated Farmland (Murders at Karlov Manor Commander #267)
Land Cap (Ice Age #357)
Lonely Arroyo (Outlaws of Thunder Junction #260)
Meandering River (Kaldheim Commander #114)
Meticulous Archive (Murders at Karlov Manor #264)
Niko Defies Destiny (Kaldheim #226)
Ojutai Monument (Dragons of Tarkir #242)
Port Town (Commander Masters #1019)
Prairie Stream (Murders at Karlov Manor Commander #281)
Razortide Bridge (Modern Horizons 2 #252)
Restless Anchorage (The Lost Caverns of Ixalan #280)
Seachrome Coast (Phyrexia: All Will Be One #258)
Sea of Clouds (Commander Legends: Battle for Baldur's Gate #360)
Seashell Cameo (Invasion #311)
Sejiri Refuge (Kaldheim Commander #118)
Skybridge Towers (Streets of New Capenna #256)
Skycloud Egg (Odyssey #309)
Skycloud Expanse (Murders at Karlov Manor Commander #294)
Study (Ravnica: Clue Edition #21)
Temple of Enlightenment (Murders at Karlov Manor Commander #302)
Tranquil Cove (March of the Machine #275)
Tundra (Vintage Masters #322)
Wanderwine Hub (Lorwyn #280)

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