Exaile is a Gtk+ music player with a simple interface. It allows powerful music management, has smart playlists, tagging features, can display album art and lyrics. It can also connect to streaming servers, download podcasts. Exaile supports secondary output devices, and there are over 50 extension plugins. It's available cross-platform.
mpg123 is a fast MPEG Audio Layer 1 / 2 / 3 decoding library and terminal playing utility. It uses floats or integer arithmetics with any available instruction set extension (3DNow, SSE, ARM) for efficiency.
VLC is a simple, fast and powerful media player with desktop and mobile cross-platform support. It can use files, network streams, CD and DVDs, webcams, DVB-T and other devices for playing. It supports a plethora of video formats like MPEG, DivX, H.263, H.264, H.265, VP9, MKV, WebM, WMV, MP3, AAC, MOD variants, FLAC, Vorbis, Theora, Dirac, FLV, MXF, and other encodings or meta formats (subtitles). It doubles as player and streaming server, and recording or transcoding and conversion tool.
Tomahawk is a music player and audio streaming service frontend for desktop usage. It manages songs, albums, playlists, meta info, social sharing. It supports various cloud services and commercial providers, such as Spotify, Beats, Google play, Soundcloud, LastFM, Hype Machine, Echo Nest, Rdio, Grooveshark, Billboard, OwnCloud, iTunes, Jamendo, Deezer, Ampache, Jabber, and Subsonic.
GRLP is a robust internet radio station stream browser and player for Linux distributions. It comes with a pre-built list of 500 known streaming stations, connects to their audio servers and plays them inline. It also allows to add new ones, or rename and regroup them. It's very customizeable and comes with many fancy window backgrounds and themes.