array_intersect.php

<?php
$array1 = array("Black","White","Navy","Royal Blue","Red","Yellow","Green","Forest Green","Light Pink","Charcoal","Carolina Blue","Sports Grey","Dark Heather","Orange","Purple","Military Green","Dark Chocolate","Natural");
$array2 = array("Black","White","Navy","Royal Blue","Red","Yellow","Green","Light Pink","Charcoal","Blue","Sports Grey","Dark Heather","Orange","Purple");
$array3 = array("Black","White","Navy","Blue","Red","Green","Grey","Orange","Purple");
$array4 = array("Black","White","Navy","Blue","Red","Green","Grey","Light Pink","Orange","Purple");
$array5 = array("Black","White","Navy","Royal Blue","Red","Yellow","Green","Forest Green","Light Pink","Dark Chocolate","Maroon","Light Blue","Sports Grey","Orange","Purple","Natural");
$array6 = array("Black","White","Navy","Royal Blue","Red","Yellow","Green","Light Pink","Charcoal","Carolina Blue","Sports Grey","Dark Chocolate","Orange","Purple","Sand");
$array7 = array("Black","White","Navy","Royal Blue","Red","Cherry Red","Cardinal Red","Yellow","Green","Forest Green","Light Pink","Charcoal","Carolina Blue","Sports Grey","Dark Chocolate","Orange","Purple","Sand","Military Green");
$array8 = array("Black","White","Navy","Blue","Red","Green","Silver","Orange","Purple","Teal");
$array9 = array("Black","White","Navy","Blue","Red","Green","Dark Grey","Purple","Pink","Turquoise");

var_dump(array_intersect($array1, $array2, $array3, $array4, $array5, $array6, $array7, $array8, $array9));