Leaf - Leaf PHP is a micro-framework that allows you to create clean, simple but powerful web applications and APIs quickly..
Laravel - A PHP Framework For Web Artisans
Fat-Free - PHP micro-framework designed to help you build dynamic and robust Web applications - fast
CodeIgniter - A Fully Baked PHP Framework
Slim Framework - Slim is a PHP micro framework that helps you quickly write simple yet powerful web applications and APIs.
CakePHP - The Rapid Development Framework for PHP