$pattern = '/b(@abdulcollo|tuskys|#teamBata|50% off|baby|@mystic_false)b/i';

$string = 'Anga lonely everyday RT @Mystic_False: Heehe @AbdulCollo aneno ka idhi tuskys in lonely bana #TeamBata in Kakamega baby! @danaceda @kibalimoreithi @olivermathenge @batakenya @ Tuskys Mega Mall 50% off';

prag_match_all($pattern, $string, $matches);

$matches = array('tuskys', 'baby', '50% off');