$re = '/\<\!-* *([A-Za-z]*) *-*\>([\s\S]*?)<!-* *(\b[A-Za-z ]*\b) *-*\>/mi';
$str = '<!-- Text --><b>Text</b>
<a href="google.com">Link</a>
<div class="col"><h1>Nested Content</h1><p>More content</p>
</div>
<!-- END of Text -->
More text <!-- Another Tag Comment -->';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php