MPlayer
MPlayer – free and open source, cross-platform media player
QMPlay2
QMPlay2 – free and open source, multiplatform video and audio player which can play most formats and codecs
Celluloid
Celluloid – free and open source, simple media player that can play virtually all video and audio formats, GTK+ frontend for mpv
SMPlayer
SMPlayer – free and open source media player with built-in codecs, with support for Youtube for Windows and Linux
Flacon
Flacon extracts individual tracks from one big audio file containing the entire album of music and saves them as separate audio files
Selene
Selene – free and open source audio/video converter for converting files to various formats
SoundConverter
SoundConverter – free and open source simple, convenient and fast audio file converter for Linux
SoundKonverter
SoundKonverter is a frontend to various audio converters, software for transfer the contents of audio CDs to your PC and convert the contents of music folders
Cozy
Cozy – free and open source a modern software for organizing and listening to audiobooks for Linux
Audio Recorder
Audio Recorder – free and open source software for recording audio from various sources