vxref provides integration of the xref tool into vim. The xref tool is a cross referencing and refactoring tool with a free version available that parses C and Java code, and a paid version that parses C++. vxref brings solid auto-completion (as opposed to all sorts of flakey varieties such as omni-complete) and accurate code browsing with scope information to vim.
PHP Autocomplete is an auto-complete and combo box component for PHP developers. A working auto-complete text box requires only two lines of PHP code. It features support for multiple dependent, cascading, nested drop-downs, customization with templates and images, the ability to quickly set up fields for tagging, built-in combo box support, and loading of remote data with built-in AJAX/JSONP support.