<?php
$regExp = "/^\\s*([+]\\s*7|8)(\W*[0-9]\W*){10}$/ui"; //регулярка для правильного номера (пока не нужна)
 
 
 
$exampleExp = "/\\W*/"; //регулярка для удаления лишних символов
 
$correctNumbers = [ 
  '84951234567',  '+74951234567', '8-495-1-234-567', 
  ' 8 (8122) 56-56-56', '8-911-1234567', '8 (911) 12 345 67', 
  '8-911 12 345 67', '8 (911) - 123 - 45 - 67', '+ 7 999 123 4567', 
  '8 ( 999 ) 1234567', '8 999 123 4567'
];
foreach($correctNumbers as $correctNumber){
	echo preg_replace($exampleExp,"+7$2",$correctNumber);
	echo "\n";
};

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