Polly!

TweetDeck aims to evolve the existing functionality of Twitter by taking an abundance of information i.e twitter feeds, and breaking it down into more manageable bite sized pieces. From a poster's point of view, it supports shortening URLs by a couple of different services, posting and hosting images at different sites, and scheduling tweets to be posted even if you're offline.

Tweetbot is a full-featured Twitter client with a lot of personality. Whether it’s the meticulously-crafted interface, sounds & animation, or features like multiple timelines & smart gestures, there’s a lot to love about Tweetbot.

Tired of seeing ads and promotions in your timeline, being disrupted by tweets from bots and people you don't like, or just want a pure Twitter experience back like the good old days? Try Twidere for Twitter!

Choqok - KDE Micro-Blogging ClientThe name comes from an ancient Persian word, means Sparrow!Currently supports Twitter.com and Identi.ca services.It currently features:

Gwibber is an open source microblogging client for GNOME developed with Python and GTK. It brings the most popular social networking web services to your desktop and gives you the ability to control how you communicate.

Corebird is a Twitter app with an interface reminiscent of Twitter’s official app for OS X

Tweetdeckr is an open source TweetDeck replacement client.

"Tweet It!" is designed with every single Windows device in mind. From phone with touch screen to desktop PC with mouse and keyboard you'll have great expirience. And Continuum support for pleasant PC like Twitter browsing when you are away from it.

Aeries is a powerful Twitter client exclusively for Windows. Aeries has been designed to make using Twitter easier than ever, all packaged together in a slickly designed app. Fall in love with Twitter again through the power of Aeries.

Fenice is a full-featured Twitter app for Windows designed to offer the best Twitter experience to every user (pro or casual ones).

Twidge is a tool for interacting with microblogging sites such as Twitter and identi.ca.

Twitux it's a free and open source GTK+ application for Twitter. you can: Send status, View friend status and see what they are doing , Send direct messages to your Twitter friends, GUI notificactions when a friend update their status.. and more :)

Tweetings is a Twitter client for Mac OS X with an extensive feature list including lists, exclusion filters, TwitLonger, GeoLocation and syncs your timeline with your iPhone or iPad!

Nymphicus is an App.net, Twitter, Facebook and QUOTE.fm client.