Jukebox-YT от Sam Boyer

Jukebox-YT is a Media Player for YouTube videos that lets you collect videos, group them into dynamic playlists and play with rating-weighted shuffling!

Videos can be added to your collection individually, or batch-imported from a playlist. From there they can be shuffled, rated and filtered through using complex expressions. Playlists can be made from these search filters.

The plugin features a main screen where the tracks are played and handled, a toolbar popup with remote control and 'Add' options in the context menus for YouTube videos and playlists.

(It should be noted that Jukebox-YT cannot play certain music videos that are disallowed from being played outside of YouTube, but most music works :3)