K-Yamo is an MP3 and Ogg Vorbis tagger with ID3v2 support. It can store ID3v1, ID3v2.3, or ID3v2.4 tags. It also stores pictures in the tags. K-Yamo supports multi-file editing. It can guess tags out of filenames, and fetches the missing parts from musicbrainz. It also cleans up your files into a structured filesystem tree which makes use of the tags in the files. Finally, it is a CD ripper with FreeDB support. A MySQL database can optionally be used for tagging.
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).
The Ultimate Live Music Audio Converter is an audio conversion tool specifically designed around the file formats used for live music trading. It currently supports conversion of SHN, FLAC, and WAV files to MP3 or Ogg. Advanced features include automatic tagging of files using the contents of a set-list file (MP3, Ogg, and FLAC only), upload of new files into Itunes Library, and scanning directories where new files are downloaded (manual or automatic).
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.
Klactoveedsedstene is a cross-platform graphical audio front-end to MPlayer. It has advanced support for album art. It recognizes embedded album art, and is also mostly able to find the correct album art from the Internet based on the Metadata tags. It features fast startup, Select and Play, an all-in-one window, and the ability to drag and drop music into the library. It supports ape, FLAC, Ogg, MP3, MPC, WAV, and WMA. It is highly configurable and stateful (remembers your window settings). All parts of the GUI can be colored. It has Album-Artist-Track view. All track columns are sortable and movable. The interface can be minimized.