Time Buddy - Time Buddy brings a colorful world clock.
Magic Playlist - Get the playlist of your dreams based on a song
Time Zone Converter - Time Zone Converter is an online productivity tool to calculate exact time across time zones.
Spotalike - Spotify playlist with similar songs, according to Last.fm
World Clock - World Clock is an app that lets you see the time of any city in the world.
Playlist Machinery - Tools that help you create & organize your Spotify playlists