VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
Jajuk - Jajuk is software that organizes and plays music using Java.
Celluloid - Celluloid (formerly GNOME MPV) is a simple GTK+ frontend for mpv. Celluloid interacts with mpv via the client API exported by libmpv, allowing access to mpv's powerful playback capabilities.
SMPlayer - SMPlayer is a free video and audio player for both Windows and Linux that allows you to play almost all media files without having to install additional codecs. Read more about SMPlayer.
Sayonara Player - Sayonara is a simple but nice audio player and holds a lot of features like a library, id3 tag...
QMPlay2 - QMPlay2 is a video and audio player which can play most formats and codecs.