30 cards where the text includes “convoke” and the color identity ≤ RUW and the set is not “mom” and the set is not “moc” and the set is not “pmom”

Hour of Reckoning (Midnight Hunt Commander #87)
Clever Concealment (Phyrexia: All Will Be One Commander #5)
Bennie Bracks, Zoologist (Murders at Karlov Manor Commander #57)
Obelisk of Urd (Zendikar Rising Commander #115)
Transcendent Message (Store Championships #16)
Chief Engineer (Commander 2016 #86)
Conclave Tribunal (Ravnica: Clue Edition #56)
Everything Comes to Dust (Doctor Who #19)
Stoke the Flames (Magic 2015 #164)
Devouring Light (Ravnica Remastered #15)
Return to the Ranks (Magic 2015 #29)
Ephemeral Shields (Magic 2015 #11)
Venerated Loxodon (Guilds of Ravnica #30)
Chant of Vitu-Ghazi (Ravnica: City of Guilds #7)
Triplicate Spirits (Magic 2015 #40)
Seraph of the Masses (Magic 2015 #32)
Peri Brown (Doctor Who #26)
Angel of Salvation (Time Spiral Remastered #3)
Conclave Phalanx (Modern Masters 2015 #12)
Conclave's Blessing (Ravnica: City of Guilds #11)
We Ride at Dawn (Outlaws of Thunder Junction Commander #12)
Crowd's Favor (Magic 2015 #138)
Flight of Equenauts (Guilds of Ravnica #11)
Martyr's Soul (Modern Horizons #19)
Loxodon Restorer (Guilds of Ravnica #20)
Will-Forged Golem (Magic 2015 #239)
Meditation Puzzle (Magic 2015 #19)
Ledev Guardian (Guilds of Ravnica #18)
Conclave Equenaut (Ravnica Remastered #13)
Ood Sphere (Doctor Who #594)

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