$re = '/^.*"hide"\s*:\s*true.*(*SKIP)(*FAIL)|"user"\s*:\s*"\K[^"]+/m';
$str = '<!-- block {"user":"josh-hart", 1234566 ,"hide":false} /-->
<!-- block {"user":"jalen-brunson", 7744633 ,"hide":true} /-->
<!-- block {"user":"julius-randle", 333333,"hide":false} /-->
<!-- block {"user":"obi-toppin", 4hh3n33n33n, /-->
<!-- block {"user":"rj-barrett", nmremxxx!! ,"hide":true} /-->
<!-- block {"user":"mitch-robinson",yahaoao /-->';
preg_match_all($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