Prepros - Compile Less, Sass, Scss, Stylus, Jade, Coffeescript, Haml and Markdown with live browser refresh.
SASS Compiler - Generate CSS code from sass source using SASS Compiler. Beautify CSS if necessary.
CodeKit - CodeKit allows you to optimize the performance of your website by automatically and efficiently compiling a variety of popular languages.
Scout-App - Process Sass files into CSS without any knowledge of the command line.
Fire.app - Fire.app is a menu bar only app for dead easy HTML prototyping.
WTOOLS.io - Free Online Web Tools. Kit of tools such as generators, minifiers, formatters, checkers, converters, seo and much more