I recently added hooks to the dropdown menu widget and using those hooks you can enlarge your navigations easily. Here i will show you how to add a categories dropdown to the end of pages menu, as seen on my site.

We can achieve this simply using dropdown_list_after hook. Here is the sample code:

function add_categories(){
  /* Open top level item and sub-list */
  echo "nt<li><a href="#cat">Categories</a><ul class="children">"; 

  /* List categories using wp function*/

  /* Close sub-list & top level */
  echo "nt</ul></li>";

  /* You can add your own links too! */
  echo "<li><a href="https://wpassist.me/">Shailan.com</a></li>";

} add_action('dropdown_list_after', 'add_categories');

You can easily append anything to the end of list using this simple function.