45 cards where the cards can be your commander and the color identity is BGRUW

Morophon, the Boundless (Commander Masters #3)
Esika, God of the Tree // The Prismatic Bridge (Kaldheim #168)
Esika, God of the Tree // The Prismatic Bridge (Kaldheim #168)
Sisay, Weatherlight Captain (Modern Horizons #29)
Ramos, Dragon Engine (Commander 2017 #55)
Jodah, the Unifier (Dominaria United #203)
Kenrith, the Returned King (The List #ELD-303)
The Ur-Dragon (Commander Masters #361)
Tiamat (Adventures in the Forgotten Realms #235)
Sliver Hivelord (Commander Masters #937)
Jodah, Archmage Eternal (Double Masters 2022 #233)
Jegantha, the Wellspring (Ikoria: Lair of Behemoths #222)
The First Sliver (Modern Horizons #200)
Go-Shintai of Life's Origin (Neon Dynasty Commander #37)
Sliver Legion (Time Spiral Remastered #261)
Najeela, the Blade-Blossom (Battlebond #62)
Scion of the Ur-Dragon (Commander 2017 #192)
Omnath, Locus of All (March of the Machine #249)
Sliver Overlord (Scourge #139)
Jenson Carthalion, Druid Exile (Dominaria United Commander #3)
O-Kagachi, Vengeful Kami (Dominaria United Commander #164)
Urtet, Remnant of Memnarch (Phyrexia: All Will Be One Commander #28)
Progenitus (Modern Masters #182)
Garth One-Eye (Modern Horizons 2 #197)
Tom Bombadil (The Lord of the Rings: Tales of Middle-earth #234)
Niv-Mizzet Reborn (War of the Spark #208)
Sliver Queen (Tempest Remastered #211)
Jared Carthalion (Dominaria United Commander #2)
Sliver Gravemother (Commander Masters #707)
Reaper King (Shadowmoor #260)
Kyodai, Soul of Kamigawa (Kamigawa: Neon Dynasty #23)
Child of Alara (Double Masters 2022 #192)
Codie, Vociferous Codex (Strixhaven: School of Mages #253)
Horde of Notions (Modern Masters 2015 #178)
Rukarumel, Biologist (Commander Masters #711)
Tazri, Beacon of Unity (Zendikar Rising #44)
Niv-Mizzet, Supreme (March of the Machine: The Aftermath #40)
Karona, False God (Scourge #138)
General Tazri (Oath of the Gatewatch #19)
Niv-Mizzet, Guildpact (Murders at Karlov Manor #220)
Cromat (Apocalypse #94)
Tazri, Stalwart Survivor (March of the Machine: The Aftermath #6)
Atogatog (Odyssey #286)
Ezio Auditore da Firenze (Assassin's Creed #25)
Vorthos, Steward of Myth (Unfinity #126)
Surgeon General Commander (Unsanctioned #72)

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