$re = '/(?si)(?:^(?<!.)|\R{2})\K(?:(?!\R{2}).)*?\bfifa\b.*?(?=\R{2}|\z)/m';
$str = 'Region: AR
OnlineID: Atl_Tuc
---Start---
FIFA 18 Legacy Edition
---END---
Region: FR
OnlineID: jubtrrzz
---Start---
FIFA 19
Undertale
Pro Evolution Soccer™ 2018
---END---
Region: US
OnlineID: Cu128yi
---Start---
KINGDOM HEARTS HD 1.5 +2.5 ReMIX
---END---
Region: RO
OnlineID: Se116
---Start---
Real Farm
EA SPORTS™ FIFA 20
LittleBigPlanet™ 3
---END---
Region: US
OnlineID: CAJ5Y
---Start---
Madden NFL 18: G.O.A.T. Super Bowl Edition
---END---';
preg_match_all($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