I am not the one who supports expensive tools, but I do use Ahref Explorer (but mostly to check Contents and links). To me Google analytic and webmasters tool are more than capable of assisting any ethical SEO campaign effectively. You can check most errors from or using Google web master tools.
You can also use Google disvow tool to check out for bad or spam backlinks for your website. Removing spam or bad backlinks will help to improve your keyword rankings in search engines.