DeaDBeeF is an audio player for GNU/Linux and other UNIX-like systems. It is written in C with some plugins in C++. It has minimal dependencies, a native GTK2 GUI, cuesheet support, support for MP3, Ogg, FLAC, and APE, chiptune formats with subtunes, song-length databases, and more. It is very fast and lightweight, and extensible using plugins (DSP, GUI, output, input, etc.). The GUI looks similar to Foobar2000.
Goggles Music Manager is a music collection manager and player that automatically categorizes Ogg Vorbis, FLAC, MP3, MP4, ASF, and Musepack files based on genre, artist, album, and song. It supports gapless playback, features easy tag editing, and allows scrobbling tracks to last-fm.
MoosicApplet is a GNOME panel applet which displays the current status of the Moosic jukebox server. It also provides some basic features for controlling the song player. It features a configurable layout and the ability to rewrite the song name in various ways to make it easier to read.
Music Player Daemon (MPD) is a server that allows remote access for playing music in various formats and managing playlists. It makes a great desktop player with frontend options (Qt, GTK, ncurses, Windows, and Web clients are available). It is also appropriate as a console player that is scriptable, and is especially useful if X is restarted frequently. A set of rapid development tools for clients are being developed and include a C library, Python module, PHP class, Perl module, and Java Class. The goals are to be easy to install and use, to have minimal resource requirements, to be stable and flexible, and easy to interface.
MOC (music on console) is a console audio player with a simple ncurses interface in playmp3list style. It supports MP3 (with ID3 tag, VBR, and Xing headers), Ogg, FLAC, WAVE, Musepack, Speex, WMA, MP4, AAC, and some other less popular audio formats. Playlists can be saved and loaded using .m3u files (PLS version 2 can also be loaded). Internet streams (Shoutcast, Icecast) are supported. It achieves gapless playback by employing an output buffer in a separate thread and file pre-caching. The key mapping can be fully customized. The interface can be detached from the server as it plays in the background.