Owlead - Grow your Twitter with valuable followers, effortless
Tweedle App - Notion is nice but sometimes all you need is an app like Tweedle.
Tweetbook.in - Tweetbook.in lets you create and save a diary like PDF ebook of tweets.
Plume - App for writing documents, scripts, books and more.
Narrow - Narrow helps you build a targeted audience and increase your influence on twitter.
Flamingo for Twitter - Flamingo for Twitter is a bright and colorful Twitter client that comes with a simple interface.