How to create node twig template suggestions for one content type?
You need to get the values first you want to work with. For example the node object is inside $variables['elements']['#node']. In the sample below field_foobar is a text field. Depending on what your field type is you may need to get the value you want a little bit differently. And also maybe sanitize it first before you use it in a template suggestion (replace spaces etc.).

/**
 * Implements hook_theme_suggestions_HOOK_alter().
 */
function MYMODULE_theme_suggestions_node_alter(array &amp;$suggestions, array $variables) {
  /** @var \Drupal\node\Entity\Node $node */
  $node = $variables['elements']['#node'];
  if ($node-&gt;bundle() === 'page') {
    if (!$node-&gt;get('field_foobar')-&gt;isEmpty()) {
      $value = $node-&gt;get('field_foobar')-&gt;first()-&gt;getValue()['value'];
      $view_mode = $variables['elements']['#view_mode'];
      $suggestions[] = 'node__page__' . $view_mode . '__' . $value;
    }
  }
}