custom admin nav menu predefined set of links

admin nav menu metabox

/**
 * @link https://gist.github.com/certainlyakey/11441175
 */
function Marvel_add_admin_nav_menu_metabox() 
{
    add_meta_box('marvel-metabox-nav-menu-custom', 'Marvel Links', 'Marvel_admin_nav_menu_metabox_callback', 'nav-menus', 'side', 'default');
}
add_action('admin_head-nav-menus.php', 'Marvel_add_admin_nav_menu_metabox');

function Marvel_admin_nav_menu_metabox_callback() 
{
    $predefined_links = [
        [
            'title' => 'Guest List',
            'type'  => 'custom',
            'url'   => '#'
        ],
        [
            'title' => 'Event Manager',
            'type'  => 'custom',
            'url'   => '#'
        ],
    ];

    $items      = [];
    $loop_index = 999999;

    foreach ($predefined_links as $link) 
    {
        $loop_index++;

        $item = new stdClass();
        $item->object_id = $loop_index;
        $item->db_id = 0;
        $item->object = 'item_type_' . $loop_index;
        $item->menu_item_parent = 0;
        $item->type = $link['type'];
        $item->title = $link['title'];
        $item->url = $link['url'];
        $item->target = '';
        $item->attr_title = '';
        $item->classes = array();
        $item->xfn = '';

        $items[] = $item;
    }

    $walker = new Walker_Nav_Menu_Checklist([]);

    ?>
        <div id="posttype-archive" class="posttypediv">
            <div id="tabs-panel-posttype-archive" class="tabs-panel tabs-panel-active">
                <ul id="posttype-archive-checklist" class="categorychecklist form-no-clear">
                    <?php echo walk_nav_menu_tree(array_map('wp_setup_nav_menu_item', $items), 0, (object) array('walker' => $walker)); ?>
                </ul>
            </div>
        </div>

        <p class="button-controls">
            <span class="add-to-menu">
                <input type="submit" <?php echo disabled(1, 0); ?> class="button-secondary submit-add-to-menu right" value="<?php _e('Add to Menu', 'marvel') ?>" name="add-custom-menu-item" id="submit-posttype-archive" />
                <span class="spinner"></span>
            </span>
        </p>
    <?php
}