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.
Flac-utils is a toolkit for managing FLAC files. Its primary usage is syncing metadata between sets of FLAC files. Flac-utils also provides a Python module called flac_compare that can be used separately. The utilitiy consist of three tools: flac-sync, which syncs a file tree of FLAC comments for files with the same audio-part; flac-diff, which compares two FLAC files' metadata information and shows the differences; and flac-add-picture, which adds album cover art to the files using Amazon.
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.
musutil includes several utilities for working with a music collection. The principle one is musview, which generates a number of "Views". Each View, analogous to a database view, is an alternative presenation of the original files. The View can selectively include only some files (based on their properties) or have files processed into into a different format, with audio filters applied, adjusted tag data, or a different filename.