WooCommerce – Return All Products On Archives

// Force archives to show all products
add_filter( 'loop_shop_per_page', 'fivetwelve_new_shop_loop', 20 );
function fivetwelve_new_shop_loop( $cols ) {
  // $cols contains the current number of products per page based on the value stored on Options -> Reading
  // Return the number of products you wanna show per page.
  $cols = -1;
  return $cols;
}