See the WordPress Codex "Action" reference (http://goo.gl/zo5vY) for a more complete list.
Runs at the beginning of every admin page before the page is rendered. If you need to display data to the admin users, this is a great action to hook into.
Runs after the basic admin panel menu structure is in place. Hook into this action when adding your own custom menu items.
Runs as meta boxes are being constructed in the manager. Meta boxes are any "extra" bit of data displayed, for example, custom fields on a post edit page.
add_action( 'do_meta_boxes', 'StandardizedCustomContent::remove_default_custom_fields', 10, 3 );
Runs after ...