$re = '/^wp-content\/uploads\/(?!(2021\/06||2021\/07)\/).+$/m';
$str = 'wp-content/uploads/2021/06/list-block-3.svg
wp-content/uploads/2021/06/list-block-3.svg
wp-content/uploads/2021/06/list-block-3.svg
wp-content/uploads/2021/07/list-block-3.svg
wp-content/uploads/may/05/list-block-3.svg
wp-content/uploads/2021/05/list-block-3.svg
wp-content/uploads/2020/02/list-block-3.svg';
preg_match_all($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