Sebastian Echeverry

This plugin allows you to use SCSS files directly in wp_enqueue_style. Just add the file to the list of styles and the plugin will compile it when necessary.
The base of this plugin is strongly influenced by the <a href="https://wordpress.org/plugins/wp-scss/" rel="ugc">WP-SCSS</a> code and extracts some ideas from <a href="https://wordpress.org/plugins/sassify/" rel="ugc">Sassify</a>. The goal is to keep the plugin updated with the latest version of <a href="https://packagist.org/packages/scssphp/scssphp" rel="nofollow ugc">scssphp</a>, remove configuration options from the graphical interface, and use the scssphp capabilities to create debug files.
This plugin is not intended to be installed by a conventional user, but to be required by templates or plugins that wish to include SCSS style files and therefore the configuration is expected to be done in the code.

SCSS-Library

Add support for using SCSS style files with wp_enqueue_style.

Ari Stathopoulos

Dimitris Kalliris

Unyson

This is a simple plugin that loads the Less.php and scssc classes and makes them available to other plugins and themes. 
When activated this plugin will not do anything. 
It has no functionality on its own, but can be used as a dependency for other plugins & themes.
Includes the Less.php class from http://lessphp.gpeasy.com/ and scss from http://leafo.net/scssphp/

Less PHP Compiler

Includes the less.php preprocessor so that it may be used by other plugins or themes.

SCSS-Library vs Less PHP Compiler