Allows searching YouTube without interrupting the video, by loading the search results in the related video bar. Also give the ability to create an "up next" list, by adding returned results to an ad-hoc playlist.
Chrome Web Store: https://chrome.google.com/webstore/detail/youtube-playlists/cmgmibjndnhopdjednaoapagmpchagmg
Background searching of videos Option of adding returned videos to a playlist which lasts the session Option to remove items from the session's playlist