Imgur's Video to GIF - Make a GIF from hundreds of video sites
Lightbeam for Firefox - Mozilla is the not-for-profit behind the lightning fast Firefox browser. We put people over profit to give everyone more power online.
Drop to GIF - Super simple movie to GIF conversion
island - a free and opensource alternative to parellel space
Yout - YouTube to Mp3 Converter
AllAccounts - AllAccounts is an extension that allows Firefox to connect to websites using different user names.