<?php

// Правильные:
$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'
];


$regexp = "/\\s?(8|[+]\\s?7)([-]?[)]?[(]?\\s?\\d[-]?[)]?[(]?\\s?){10}/";

foreach($correctNumbers as $number){
    $match = [];
    echo "Строка $number\n";
    if(preg_match($regexp, $number, $match)){
        echo "Найден номер $number\n\n";
    }
    else {
        echo "Номер не найден\n\n";
    }
}