以下是显示在导航菜单界面左侧最上方的元框示例：

/**
 * Instantiates the class
 */
add_action( \'admin_init\', array( \'call_someClass\', \'init\' ) );

/**
 * The Class
 */
class call_someClass {
    const LANG = \'exch_lang\';

    public static function init() {
    $class = __CLASS__;
    new $class;
    }

    public function __construct() {
    // Abort if not on the nav-menus.php admin UI page - avoid adding elsewhere
    global $pagenow;
    if ( \'nav-menus.php\' !== $pagenow )
                    return;

        $this->add_some_meta_box();
    }

    /**
     * Adds the meta box container
     */
    public function add_some_meta_box(){
        add_meta_box(
            \'info_meta_box_\'
            ,__( \'Example metabox\', self::LANG )
            ,array( $this, \'render_meta_box_content\' )
            ,\'nav-menus\' // important !!!
            ,\'side\' // important, only side seems to work!!!
            ,\'high\'
        );
    }

    /**
     * Render Meta Box content
     */
    public function render_meta_box_content() {
        echo \'<p>Example text</p>\';
    }
}

            ,\'nav-menus\' // important !!!
            ,\'side\' // important, only side seems to work!!!

遗憾的是，在撰写本文时，无法向单个菜单项本身添加额外字段，例如链接、页面等，因为这些字段是硬编码的。您可以通过jQuery添加它们，然后在需要时通过后端的挂钩保存它们。

由于@TomJNowell已经回答了元框，我只向您展示如何获取帖子类型列表：

/**
 * Builds a html form element list depending on the param type
 * 
 * @param string $type | form element type; Valid: select/checkbox/radio
 * @param bool $echo | (optional) print or return
 * @return string $html
 */
public function get_post_types_list( $type, $echo = false )
{
    $name = \' name="nav-menu-post-types\';
    $html = ! in_array( $type, array( \'checkbox\', \'radio\' ) ? "<{$type}{$name}\'>" : \'\';
    foreach( array_keys( $GLOBALS[\'wp_post_types\'] ) as $pt )
        $html .= \'select\' === $type ? "<option>{$pt}</option>" : "<input type=\'{$type}\' {$name}[]\' value=\'{pt}\' />";
    $html .= ! in_array( $type, array( \'checkbox\', \'radio\' ) ? "</{$type}>" : \'\';

    if ( $echo ) 
        return print $type;
    return $type;
}

@kaiser解决方案的替代方案是get_post_types() 作用它应该允许您更好地控制帖子类型。