WooCommerce change the number of products per row. You still have to write CSS so each of the products fit in there.

functions.php

<?php
// change the number of products per row
add_filter( 'loop_shop_columns', 'patricks_loop_columns', 20 );
function patricks_loop_columns() {
	return 5; // the number of products per row
}

// you still need to add CSS to make it look right. In Storefront you can add this to your style.css file.
// @media (min-width:768px){
//     .products .product {
//         max-width: 15%;
//     }
// }