A set PHP functions that SHOULD have been part of PHP's core libraries.
WordPress Cleanup and Basic Options Functions is a utility plugin, even though it's was developed with a focus on developers as many functionalities are what you might just add to every new website you build, it's really easy to use, just check the boxes corresponding to the set up you want.
A collection of useful PHP functions, mini classes and snippets that you need and can use every day.
Basic functions for handling mime-types, forked from Joe Gregorio's mimeparse library
A very simple project for PHPUnit testing using a basic calculator functions.
A PHP Class that uses PDO to connect to a MySQL Database and some basic helper functions
A great starter blank theme using basic HTML5 and semantic elements without the fluff. Includes commonly used WordPress functions.