audiopreview is a command-line tool that plays previews of many audio file types (Ogg, MP3, etc.), video file types (AVI, MPEG, Real, etc.), and Internet streams. It can also be used as a regular command-line media file player (i.e. play the files entirely like yauap or mpc123 would).
SQL Tagger reads the tags of audio files from a directory, loads them into a temporary SQLite database, accepts SQL queries to modify this database, then saves any changes back to the audio files. It's useful for performing complex updates that would be difficult or tedious with conventional taggers. It's a complement to conventional taggers, not a replacement.