https://codecanyon.net/item/wp-domain-checker/9959666

WP Domain Checker is a WordPress plugin which allow you easily to check domain name availability from your wordpress site. You can check or search for any generic top-level domains (gTLD) or country-code top-level domains (ccTLD). WP Domain Checker is made with AJAX and easily to use with Shortcode or Widget also integrated with WHMCS & WooCommerce.