Drupal 7, Views: Alter field output in table display.

module.php

<?php

/**
 * Implements hook_preprocess_HOOK().
 *
 * Marks projects that have a reference in content overview.
 */
function MODULE_preprocess_views_view_field(&$vars) {
  if(!empty($vars['view']->MODULE_foo) && $vars['field']->field_alias === 'node_type') {
    if(!empty($vars['view']->MODULE_foo[$vars['row']->nid])) {
      $suffix = ', <i>with SUFFIX</i>';
      $vars['output'] .= $suffix;
      // Views tokens use the value from views_field_handler::$last_render.
      $vars['field']->last_render .= $suffix;
    }
  }
}