Maker Swipe File - 100+ high-performing Tweets to help you grow your audience
Hum - Songwriting for iPhone
Narrow - Narrow helps you build a targeted audience and increase your influence on twitter.
Songcraft.io - A platform for songwriters to write, organize & collaborate.
Tweetflick - Save, organize & find Tweets to get the most out of Twitter
Tape It - App for songwriting & audio recording.