VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
Helium Music Manager - You can take control of your music collection.
MPV - MPV is an audio and movie player based on MPlayer and mplayer2.
BookCAT - BookCAT is a powerful book collector database program which will help you catalog a book collection...
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.
Music Collection - This Music Collection Software allows you to organize your music collection including CDs, MP3s or vinyl records into a fully searchable database.