Skip Tunes - Control iTunes, Spotify, or Rdio from your Mac's menubar
Sharingbuttons.io - Quickly generate social sharing buttons with a tiny performance footprint.
Baritone - Spotify controls that live in your menubar.
Simple Sharing Buttons Generator - Share to Facebook, Twitter, Google+, and other social networks using simple HTML buttons
Soundiiz - Transferring playlists between various music streaming platforms.
Social Share Kit - Library of CSS/JavaScript social sharing tools