page-template-list.php

<?php get_header(); ?>
<div class="container-narrow mt-80">
  <?php
  function list_pages_for_template($template_name) {
    echo '<strong>';
    echo $template_name;
    echo '</strong>';

    $args = array(
      'post_type' => 'page',
      'posts_per_page' => -1,
      'meta_query' => array(
        array(
          'key' => '_wp_page_template',
          'value' => $template_name
        )
      )
    );
    $the_pages = new WP_Query( $args );
    if( $the_pages->have_posts() ){
      while( $the_pages->have_posts() ){

        $the_pages->the_post();
        echo '<li>';
        the_title();
        echo '</li>';
      }
    }
    wp_reset_postdata();
  }

  $templates = array(
    'template-master.php',
    'template-integrations.php',
    'template-landing.php'
  );

  foreach($templates as $template) {
    echo '<div class="mt-40">';
    list_pages_for_template($template);
    echo '</div>';
  }
  ?>
</div>
<?php get_footer(); ?>