Two death metal bands went by the name Oppressor. The more famous death metal act from Chicago that shares members with rock group Soil, and a Polish band that eventually changed its name to Baphomet's Throne in 1998 to avoid confusion with the Chicago based act.
These are photos from concerts where Oppressor played, so they may be of other bands that played the concert as well.
Maryland Deathfest XIX (Market Place/Power Plant Live Friday) May 24, 2024 Baltimore, Maryland, United States Uploaded by Nbungerko
Milwaukee Metalfest XI Jul 26 - 27, 1997 Milwaukee, Wisconsin, United States Uploaded by Pathological Mastermind
Milwaukee Metalfest 1994 Aug 5 - 6, 1994 Milwaukee, Wisconsin, United States Uploaded by Pathological Mastermind