Phalcon is described as 'high-performance PHP web framework based on the model–view–controller (MVC) pattern. Originally released in 2012, it open-source framework licensed under the terms of the BSD License (from wikipedia)' and is an app in the Development category. There are more than 10 alternatives to Phalcon for a variety of platforms, including Mac, Windows, Linux, Online / Web-based and Self-Hosted solutions. The best alternative is Laravel, which is both free and Open Source. Other great apps like Phalcon are Symfony (Free, Open Source), CodeIgniter (Free, Open Source), CakePHP (Free, Open Source) and Mako Framework (Free, Open Source).
Nette Framework is a popular tool for PHP web development. It is designed to be the most usable as possible and is definitely one of the safest one. It speaks your language and helps you to easily build better websites.
Extending the art & spirit of PHP, Zend Framework is based on simplicity, object-oriented best practices, corporate friendly licensing, and a rigorously tested agile codebase. Zend Framework is focused on building more secure, reliable, and modern Web 2.
Backdrop CMS is a simple, lightweight, and easy to use Content Management System used to build attractive, professional websites. Use it for everything from a single-administrator's personal blog site, to a complex, multi-role, business e-commerce platform.