For those with legal backups:
In the emulation scene, ROM sets are often numbered by the total count of unique game dumps. The "NeoGeo 590 set" refers to a collection of approximately 590 NeoGeo ROM images that were known to work with specific versions of Kawaks and Nebula emulators around the mid-to-late 2000s. neogeo 590 roms emulador kawaks 2021
By 2021, this number had become a nostalgic reference point for several reasons: For those with legal backups: In the emulation