CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.
Prepros - Compile Less, Sass, Scss, Stylus, Jade, Coffeescript, Haml and Markdown with live browser refresh.
Fire.app - Fire.app is a menu bar only app for dead easy HTML prototyping.
SiteFlow - The life-saver app for web developers !
Compass CSS - Compass is an open-source CSS Authoring Framework.
Flow - Stop managing projects from your inbox.