Remove WooCommerce default product sorting options

// Modify the default WooCommerce orderby dropdown

function my_woocommerce_catalog_orderby( $orderby ) {
	unset($orderby["menu_order"]);	// Remove "Default sorting"
	unset($orderby["popularity"]);	// Remove "Sort by popularity"
	unset($orderby["rating"]);		// Remove "Sort by average rating"
	unset($orderby["date"]);		// Remove "Sort by newness"
	unset($orderby["price"]);		// Remove "Sort by price: low to high"
	unset($orderby["price-desc"]);	// Remove "Sort by price: high to low"
	return $orderby;
}
add_filter( "woocommerce_catalog_orderby", "my_woocommerce_catalog_orderby", 20 );