VLC Media Player - VLC is a free and open source cross-platform multimedia player and framework.
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.
QMPlay2 - QMPlay2 is a video and audio player which can play most formats and codecs.
bomi - a powerful and easy-to-use multimedia player
MPV - MPV is an audio and movie player based on MPlayer and mplayer2.