$re = '/(?:\[.*\]\((?:https://)(?:media|cdn)(?:\.discordapp\.)(?:net|com)(?:/(?:attachments|emojis|stickers)/.*\)))?(\[.*\]|[^\[]*)(?:\[.*\]\((?:https://)(?:media|cdn)(?:\.discordapp\.)(?:net|com)(?:/(?:attachments|emojis|stickers)/.*\)))?/m';
$str = '[k9_et_PAT](https://cdn.discordapp.com/emojis/1290159554080018432.gif?size=48&animated=true&name=k9_et_PAT)
[RoloHeadpat](https://media.discordapp.net/stickers/1331814642959515699.png?size=160&name=RoloHeadpat)
[funny_meme](https://cdn.discordapp.com/attachments/408346996823556097/1357753754514100364/NO-WAY-1743754818196.png?ex=67f2abb8&is=67f15a38&hm=2481a2440e02712ff422d605416d1395c973144e51d2e882e7615fbd15a53372&)
[totally_malicious](google.com)
a[k9_et_PAT](https://cdn.discordapp.com/emojis/1290159554080018432.gif?size=48&animated=true&name=k9_et_PAT)
a[RoloHeadpat](https://media.discordapp.net/stickers/1331814642959515699.png?size=160&name=RoloHeadpat)
a[funny_meme](https://cdn.discordapp.com/attachments/408346996823556097/1357753754514100364/NO-WAY-1743754818196.png?ex=67f2abb8&is=67f15a38&hm=2481a2440e02712ff422d605416d1395c973144e51d2e882e7615fbd15a53372&)
a[totally_malicious](google.com)';
preg_match_all($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