$re = '/href.+?[\'|\"]+?([^\'|\"]+)?[\'|\"]/m';
$str = '<a href=\'http://matrix.ms.com/" target="_blank" data-saferedirecturl="https://www.google.com/url?q=http://matrix.ms.com/&source=gmail&ust=1591284067791000&usg=AFQjCNGSmpctZFZau9kOCv8xa9Abu8a-uQ">Matrix.ms.com</a>
<a href="http://matrix.ms.com/" target="_blank" data-saferedirecturl="https://www.google.com/url?q=http://matrix.ms.com/&source=gmail&ust=1591284067791000&usg=AFQjCNGSmpctZFZau9kOCv8xa9Abu8a-uQ">Matrix.ms.com</a>
a.+?href.+?[\\\'|\\"]+?([^\\\'|\\"]+)?[\\\'|\\"]';
preg_match_all($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