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.
Choqok - Choqok - KDE Micro-Blogging Client The name comes from an ancient Persian word, means Sparrow!
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.
TweetCaster - TweetCaster is a third-party Twitter mobile app that is available on Google Play and the Apple App Store.
Earthquake - Terminal-based Twitter Client with Streaming API support. Only supports Ruby 1.9 and later.