How to create one node tpl files for multiple content types? In my site I have 10-15 content types that have the exact same node template layout. Like node--productone.tpl.php, node--producttwo.tpl.php etc...

How can i create one node tpl files for that similar type of content types?
Yes you can. Here is the example:

function YOURTHEMENAME_preprocess_node(&amp;$variables) {
  if ($variables['node']) {
    $node = $variables['node'];
    switch ( $node-&gt;type ) {
      case 'type1':  // Replace with your actual content types
      case 'type2':
      case 'type3':
      // looks for node--common.tpl.php in your theme directory
      $variables['theme_hook_suggestion'] = 'node__common';
      break;
    }
  }
}