Show a pending posts count on Custom Post Type menu label like Plugin Update Notification count. Thanks to Samik Chattopadhyay for the nice snippet.

pending-post-bubble-in-admin-menu.php

/**
 * Get posts pending count as per Post Type.
 * @param  string $post_type
 * @return integer            Pending count.
 */
function project_get_pending_items( $post_type ) {
    global $wpdb;
    $pending_count = $wpdb->get_var( $wpdb->prepare( "SELECT COUNT(*) FROM $wpdb->posts WHERE post_type = %s AND post_status = 'pending'", $post_type ) );
    return (int) $pending_count;
}

/**
 * Show pending count on menu.
 * @return integer pending count beside menu label.
 * @author Samik Chattopadhyay
 * @link http://stackoverflow.com/a/8625696/1743124
 */
function notification_bubble_in_my_custom_post_type_menu() {
    global $menu;
    $pending_items = project_get_pending_items( 'my_custom_post_type' );
    //while registering a post type the 'menu_position' is important, here our value was 7
    $menu[7][0] .= $pending_items ? " <span class='update-plugins count-1' title='title'><span class='update-count'>$pending_items</span></span>" : '';
}
add_action('admin_menu', 'notification_bubble_in_my_custom_post_type_menu');