MPV
MPV is an open-source. cross-platform video player that is designed with a minimalist, graphic-al user interface and has rich features on the command line version. It features a minimalistic approach which makes using it easy for even beginners. This is basically designed to work on popular and common operating systems like Windows, Android, and Linux and it works on the Ubuntu system as well. MPV is a powerful video player as it has the ability to play videos from the GNOME shell desktop too. 
 
Why you must get it: 
MPV is considered to be a clean yet powerful video player. Displaying DVD menus, ca sting content to a Chromecast, etc. are some of the media handling features of this video player. MPV has its own salient features like improving the picture and sound quality to the maximum possible resolution. It sports a minimalistic GU I with few necessary controls and video codecs support.
         It even supports YouTube and other streaming  command lines along with support for subtitles while the video is being played.