There is only one file type that uses the .VFS0 extension:
Metro 2033 Sound File
Game file used by Metro 2033 and Metro: Last Light, a post-apocalyptic video game that takes place in Moscow; contains .OGG sound files used by the game for music and sound effects.
NOTE: You need the Metro 2033 Mod Tools to assist you in extracting the OGG files from the VFS0 file.
sounds.vfs0 - The most common name of the VFS0 file, which contains the sounds for the game.
Updated: May 24, 2015