$re = '/\[[^\[]*[^\]]*\]/i';
$str = '[products-tab collection="frontpage,new,all-1" title="BEST SELLING" nav="true" style="product-loop-swatch" rows="2" items="8" header="style-1"]
[products-deal product="apple-iphone-se,armani-exchange-brown-leather-watch-ax2181" title="DEAL OF THE DAY"]
[blog blog="news" desc="If you are interested in the latest articles in the industry, take a sneak peek at our blog. You’ve got nothing to loose!" style="style-2"]
';
preg_match_all($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