Trionic Labs

SASS is a programmable approach to stylesheets which really adds some cool features. It can make a stylesheet easier to read, easier to update and also adds some powerful features like functions, variables and imports. (See http://sass-lang.com/docs/yardoc/file.SASS_REFERENCE.html for more details.)
This plugin enables any WordPress Theme to use SASS stylesheets. In a wordpress theme, the comments at the top of style.css are used to define the theme. For this reason, this plugin will not allow a .sass or .scss file named ‘style’.

WordPress SASS

This plugin provides automated SASS stylesheet generation.

Tom Baumgarten

SCS is a simple plugin to compile SCSS files on-the-fly, when request ask inexistent CSS file, but where SCSS file with the same name exist. Made by developers, for developers.

Simple Compiler SCSS

A simple plugin to compile scss file into css when css asked. Best for developers.

WordPress SASS vs Simple Compiler SCSS