27 cards where the full Oracle text includes “shield counter”

Aegis of the Legion (Ravnica: Clue Edition #22)
Agent's Toolkit (New Capenna Commander #66)
Boon of Safety (Streets of New Capenna #4)
Brokers' Safeguard (Alchemy: New Capenna #20)
Brokers Veteran (Streets of New Capenna #36)
Brotherhood Outcast (Fallout #12)
Call In a Professional (Streets of New Capenna #103)
Contractual Safeguard (New Capenna Commander #14)
Dapper Shieldmate (Streets of New Capenna #9)
Diamond City (Fallout #147)
Disciplined Duelist (Streets of New Capenna #182)
Elspeth Resplendent (Streets of New Capenna #11)
Falco Spara, Pactweaver (Streets of New Capenna #186)
Family's Favor (New Capenna Commander #59)
Kros, Defense Contractor (New Capenna Commander #7)
Perrie, the Pulverizer (New Capenna Commander #5)
Rhox Pummeler (Streets of New Capenna #155)
Rigo, Streetwise Mentor (Streets of New Capenna #215)
Sanctuary Warden (Streets of New Capenna #30)
Shield Broker (New Capenna Commander #29)
Singer of Swift Rivers (The Lost Caverns of Ixalan Commander #98)
Spara's Bodyguard (Alchemy: New Capenna #28)
Swooping Protector (Streets of New Capenna #33)
Titan of Industry (Streets of New Capenna #159)
Undercover Operative (Streets of New Capenna #63)
Voice of the Vermin (Streets of New Capenna #163)
Wingshield Agent (Streets of New Capenna #64)

Though this query has ended, its relics still slumber in New Argive.