ImageOptim - Faster web pages and apps.
AquaSnap - Too many windows on your screen? Stop wasting your productivity.
Transmit - Transmit is an FTP client for Mac OS X and Mac OS Classic (which is unsupported).
Moom - Move your mouse over the green zoom button in any window, and Moom's mouse control overlay will appear (as seen in the above animation).
CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.
Mizage Divvy - Divvy is an entirely new way of managing your workspace.