Plugin Check is a validation tool for PHP developers (and a quality checker for end users) to locate undefined functions and methods.
Developer Tool: Redefines the functions plugin_dir_url, plugins_url to work properly if you have symbolic links in your WordPress installation.
This plugin restricts different role users from uploading files of selected types.
This plugin reroutes all outgoing emails from a WordPress site (sent using the wp_mail() function) to a predefined configurable email address.
Provides convenient methods for developers to debug buggy code.
This plugin integrates the great Krumo class in WordPress which allows debugging of objects and variables in a well formated and structured form.
Allows you to view all WP Cron events. Handy for development.