$re = '/(\[\[(\w+|\s)*\|)/';
$str = '"[[Elemental HERO Flame Wingman]]" + "[[Elemental HERO Sparkman]]"
Must be [[Fusion Summon]]ed and cannot be [[Special Summon]]ed by other ways. This card gains 300 [[ATK]] for each "[[Elemental HERO]]" card in your [[Graveyard]]. When this card [[destroy]]s a [[Monster Card|monster]] [[Destroyed by Battle|by battle]] and [[send]]s it to the Graveyard: Inflict [[Effect Damage|damage]] to your opponent equal to the ATK of the destroyed monster in the Graveyard.';
preg_match_all($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