VideoJS - VideoJS is an HTML5 Video Player, built with Javascript and CSS, with a fallback to a Flash video...
CONV. - Convert YouTube video to MP3, GIF or MP4
Plyr - A simple, accessible and customisable HTML5 media player
Downie - Video download for OS X. Downie supports at this moment over 1,000 different sites.
MediaElement.js - MediaElement.js provides HTML5 audio and video players in pure HTML and CSS.
Yout - YouTube to Mp3 Converter