How to hide or remove unwanted widgets on Multisite installation?

I am using Multi-site installation. I don’t want all the widgets to appear under widgets.php on the dashboard. So I tried to find a way to remove or hide unnecessary widgets. So that the new sub-sites created under my Multi-site won’t have many widgets. That way the users won’t get confused with a lot of widgets.

I tried to find the files related to widgets. But I was unable to find such pages in both wp-admin/includes/widgets.php and wp-admin/widgets.php.

I also tried to find in the theme files, but failed. Could anyone help me finding these?

Or do I have a chance to hide them using functions.php?

Add this to your functions.php file:

function jpb_unregister_widgets(){
  unregister_widget('WP_Widget_Pages');
  unregister_widget('WP_Widget_Calendar');
  unregister_widget('WP_Widget_Archives');
  unregister_widget('WP_Widget_Links');
  unregister_widget('WP_Widget_Meta');
  unregister_widget('WP_Widget_Search');
  unregister_widget('WP_Widget_Text');
  unregister_widget('WP_Widget_Categories');
  unregister_widget('WP_Widget_Recent_Posts');
  unregister_widget('WP_Widget_Recent_Comments');
  unregister_widget('WP_Widget_RSS');
  unregister_widget('WP_Widget_Tag_Cloud');
  unregister_widget('WP_Nav_Menu_Widget');
}

add_action( 'widgets_init', 'jpb_unregister_widgets' );

This will get rid of all default widgets. If you want to keep a certain widget, remove that line from the function above.