20 cards where (the card is available on Paper) and the flavor text contains “song of all”

Abiding Grace (Modern Horizons 2 #1)
Cessation (Urza's Legacy #4)
Congregate (Dominaria Remastered #4)
Crucible of Worlds (Double Masters 2022 #393)
Defensive Formation (Urza's Saga #9)
Disenchant (Masters 25 #12)
Invoke the Divine (Core Set 2019 #16)
Linvala, Keeper of Silence (Secret Lair Drop #1289)
On Serra's Wings (Commander Legends #380)
Pegasus Charger (Urza's Saga #30)
Planar Birth (Urza's Saga #31)
Purify (Urza's Legacy #19)
Serra Avenger (Time Spiral Remastered #41)
Serra's Embrace (Urza's Saga #47)
Sunblast Angel (Secret Lair Drop #1290)
Voice of Duty (Urza's Destiny #23)
Voice of Grace (Urza's Saga #54)
Voice of Law (Urza's Saga #55)
Voice of Reason (Urza's Destiny #24)
Voice of Truth (Nemesis #25)

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