Code snippet to skip certain WooCommerce products from final packaging. Works only with WooCommerce Shipping Plugins from PluginHive: https://www.pluginhive.com/product-category/woocommerce-plugin/woocommerce-shipping/

gistfile1.txt

add_filter('wf_shipping_skip_product','skip_my_products',10,3);

function skip_my_products($skip = false, $product, $package){
	$shipping_free_classes = array(16); // array of shipping class ids to exclude from cart
	
	$shipping_class = $product['data']->get_shipping_class_id();
	
	if(in_array($shipping_class, $shipping_free_classes)){
		$skip = true;
	}
	return $skip;
}
// In the above code, $shipping_free_classes contains the shipping class IDs which need to be excluded from the cart. 
// $shipping_class contains the shipping class IDs of the products which are present in the cart. 
// If $shipping_free_classes contains $shipping_class, then assign true to $skip and return it.