28 cards where the illustration contains “simic-symbol”

Amateur Auteur (Unstable #3a)
Awe for the Guilds (Dragon's Maze #31)
Bond of Flourishing (War of the Spark #155)
Breeding Pool (Ravnica: Clue Edition #275)
Case of the Shattered Pact (Murders at Karlov Manor #1)
Dovin's Acuity (Ravnica Allegiance #168)
Guildmages' Forum (Guilds of Ravnica #250)
Guild Summit (Guilds of Ravnica #41)
Gyre Sage (Gatecrash #123)
Maze's End (Dragon's Maze #152)
Murder (Murders at Karlov Manor #95)
Niv-Mizzet, Guildpact (Murders at Karlov Manor #220)
Niv-Mizzet, Guildpact (Murders at Karlov Manor #319)
Niv-Mizzet, Guildpact (Murders at Karlov Manor #368)
Pillar of the Paruns (Dissension #176)
Relics of the Rubblebelt (Alchemy: Murders at Karlov Manor #19)
Renounce the Guilds (Dragon's Maze #5)
Scrutiny of the Guildpact (Alchemy: Murders at Karlov Manor #1)
Seal of the Guildpact (Commander 2015 #54)
Simic Charm (Gatecrash #195)
Simic Cluestone (Dragon's Maze #145)
Simic Guildgate (Ravnica Allegiance #257)
Simic Guildgate (Gatecrash #246)
Simic Keyrune (Gatecrash #237)
Simic Locket (Ravnica Allegiance #240)
Simic Signet (Commander 2013 #258)
Simic Signet (Dissension #166)
Vannifar, Evolved Enigma (Murders at Karlov Manor #323)

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