TubeLister - Generate a YouTube playlist from your opened tabs.
Playlist Machinery - Tools that help you create & organize your Spotify playlists
OrganizeTube - Create video playlists from Youtube, Vimeo and other sources
Playmoss - Create playlists from YouTube, Vimeo and SoundCloud
Learnamic - Free and paid K-12 learning resources from hundreds of providers, including educational apps, YouTube videos, online classes, printable worksheets, and more.
Audioship - Upload audio to YouTube or Facebook