A free app for Android, by Leav Jenn.

Lj Video Downloader is a great app for downloading all the popular video formats from websites. You can choose from the most popular formats like mp4, m3u8, and mpd. With this tool, you can download videos from any website and store them locally on your phone. The downloader supports all the major websites, like YouTube, Vimeo, VEVO, Dailymotion, Deezer, Soundcloud, Facebook, Twitter, Twitch, MTV, BBC, E! Entertainment, CNN, Comedy Central, and many more. 

You don’t need to install any plugins or addons to watch the videos. All you need is a web browser and your phone or tablet’s internet connection.