Audacious is an open-source audio player software focused on low resource use, high audio quality, and support for a wide range of audio formats.
DeaDBeeF is a modular, cross-platform audio player that plays a variety of audio formats, converts between them, lets you customize the UI in almost any way you want, and use many additional plugins which can extend it even more.
Tauon Music Box
Tauon Music Box is a modern, streamlined music player app that's packed with features! An emphgasis on playlists and drag and drop importing puts you in control of your music library! Faded volume control, 24bit FLAC support and gapless playback provides the ultimate listening experience!
aTunes is an open-source audio player with MPlayer as its playback engine. It supports MP3, Ogg Vorbis, FLAC, and other formats. aTunes allows users to edit tags, organize music, and more.
MediaMonkey is a digital media player and media library app that helps you organize and manage your music and video collection.
MusicBee is a Windows application that lets you manage, search, and play music files. Podcasts, web radio stations, and SoundCloud integration are all supported by MusicBee.