Debug Bar Post Types adds a new panel to the Debug Bar with detailed information about registered post types. Requires "Debug Bar" plugin.

Debug Bar Shortcodes adds a new panel to the Debug Bar that displays the registered shortcodes for the current request.

Debug Bar Localization adds a new panel to the Debug Bar which displays information on the locale for your install and the language files loaded.

Debug Bar Taxonomies adds a new panel to the Debug Bar with detailed information about registered taxonomies. Requires "Debug Bar" plugin.

Debug Bar Plugin Activation adds a new panel to the Debug Bar which displays plugin (de-)activation and uninstall errors.

Debug Bar Constants adds three new panels to the Debug Bar that display the defined WP and PHP constants for the current request.

Black Bar is an unobtrusive Debug Bar for WordPress developers that attaches itself to the bottom of the browser window.