Drupal theme hooks to add a template suggestion for labels based on the associated input type

drupalsouth.theme

<?php

/**
 * Implements hook_preprocess_HOOK().
 */
function drupalsouth_preprocess_form_element(array &$variables) {
  $variables['label']['#attributes']['data-element-type'] = $variables['element']['#type'];
}

/**
 * Implements hook_theme_suggestions_HOOK_alter().
 */
function drupalsouth_theme_suggestions_form_element_label_alter(array &$suggestions, array $variables) {
  if (isset($variables['element']['#attributes']['data-element-type'])) {
    $hook = str_replace('-', '_', $variables['element']['#attributes']['data-element-type']);
    $suggestions[] = "form_element_label__{$hook}";
  }
}