SQL Injection Cheat Sheet : Samples are provided to allow reader to get basic idea of a potential SQL Injection attack and almost every section includes a brief information about...
Grav : Grav is a modern open source flat-file CMS written in PHP
Stack Overflow : Stack Overflow is a question and answer site for professional and enthusiast programmers.
WebPlatform.org : Web Platform Docs is a community-driven site that aims to become a comprehensive and authoritative source for web developer documentation.
Mautic : Mautic is marketing automation software (email, social & more). Social Media Marketing, Contact Management, Email Marketing, Forms, Campaigns, Reports
This is a collection of known design patterns and some sample code how to implement them in PHP. Every pattern has a small list of examples (most of them from Zend Framework, Symfony2 or Doctrine2 as I'm most familiar with this software).