Personally, I feel overwhelmed looking at the ocean of metatags presented on the node edit page when the metatag module is installed.

How much more overwhelmed would a regular ol’ user feel?

I created a small modules to hide the extra form elements from the metatag module:

metatag_limit.module:

use \Drupal\Core\Render\Element;

// Add metatag key/value categories here to be preserved.
const ALLOWED_METATAGS = array(
‘basic’ => array(‘title’, ‘description’),
// ‘advanced’ => array(),
‘open_graph’ => array(‘og_title’, ‘og_description’, ‘og_image’),
‘twitter_cards’ => array(‘twitter_cards_description’, ‘twitter_cards_title’, ‘twitter_cards_image’)
);

function limit_metatags_form_node_form_alter(&$form, \Drupal\Core\Form\FormStateInterface $form_state, $form_id) {
if (!empty($form[‘field_meta_tags’][‘widget’][0])) {
$el =& $form[‘field_meta_tags’][‘widget’][0];
foreach (Element::children($el) as $tag_type_name) {
if (!isset(ALLOWED_METATAGS[$tag_type_name])) {
$el[$tag_type_name][‘#access’] = FALSE;
continue;
}
if (isset($el[$tag_type_name])) {
foreach (Element::children($el[$tag_type_name]) as $tag_name) {
if (!in_array($tag_name, ALLOWED_METATAGS[$tag_type_name])) {
$el[$tag_type_name][$tag_name][‘#access’] = FALSE;
}
}
}
}
}
}

metatag_limit.info.yml: 

name: Limit Metatags
type: module
description: 'Limit the number of metatags shown to editors'
core: 8.x

dependencies:
  - metatag