Gwibber - Gwibber is an open source microblogging client for GNOME developed with Python and GTK.
Flamingo for Twitter - Flamingo for Twitter is a bright and colorful Twitter client that comes with a simple interface.
TweetDeck - TweetDeck is your personal browser for staying in touch with what’s happening now.
Tweeticide - Tweeticide – Delete All Tweets is a commercial app that enables you to delete all of your tweets at once.
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.
Twicca - Twicca is a Twitter client for Android that is simply awesome. Features: * Notification