One of the best SEO tools available is Google Search Console. And it is also one of the most neglected. Google Search Console (formerly known as Webmaster Tools) is a collection of tools that help you keep your website healthy and compatible with Google. But it does much more than that.
Not only can it help you diagnose any technical SEO issues, but it can also help you figure out which pages are your most popular, see where you rank and help you increase your organic traffic. Google Search Console (or GSC) is completely free and any website, regardless of the platform it is built on, can use it.