Hypegrowth - Hypegrowth is a personal Twitter assistant that allows to grow Twitter audience.
Janetter - Janetter is a Twitter client application. Faster, smarter, and more powerful.
Jooicer - Superpowers to boost your Twitter Growth
Tweetbot - Sync your timeline across your iPhone, iPad, and Mac. Mute tweets by user, hashtag, tweet source, or keywords (including regex). 3rd Party support for image, video, read later, and timeline sync services.
Toolset.co - Twitter growth made easy, a bunch of tools to easily manage and grow your Twitter account.
YoruFukurou - YoruFukurou (NightOwl) is a Twitter client for Mac OS X, designed for Twitter addicts.