-ist: This suffix is used to indicate someone who belongs to or identifies with a particular subculture. For example, a "punkist" is someone who identifies with the punk subculture.
-ism: This suffix is used to refer to the ideology, beliefs, or practices of a subculture. For example, "goth-ism" refers to the ideology and aesthetics of the goth subculture.
-er: This suffix is less common but can be used to indicate a member of a specific subculture. For example, "gamer" can be considered someone who belongs to the gaming subculture.
Other options: Sometimes, specific subcultures use their own unique terms to refer to their members or their culture. For example, "headbanger" is used to refer to someone who enjoys heavy metal music.
Ultimately, the best way to determine the appropriate term depends on the specific subculture you are referencing and the context in which you are using it.