Gwibber - Gwibber is an open source microblogging client for GNOME developed with Python and GTK.
TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
Twitterfall - Twitterfall is an excellent choice if you want something basic, free and without much branding.
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.
Tweetdeckr - Tweetdeckr is an open source Tweetdeck replacement client.
Socialite - History Ever since we acquired Socialite from Realmac Software in December 2010, we have been planning on releasing a faster, more stable version 2.