Skip Tunes - Control iTunes, Spotify, or Rdio from your Mac's menubar
Bowtie - Bowtie is a desktop accessory that allows you to see and control your music (iTunes, Spotify...
Baritone - Spotify controls that live in your menubar.
Muzzy - it’s a tiny and gorgeous iTunes companion that lives on your menu bar. For Mac OSX, its free!
Soundiiz - Transferring playlists between various music streaming platforms.
Owlead - Grow your Twitter with valuable followers, effortless