There are a number of free SEO tools that can help you optimize your website for search engines. Here are some of the most popular ones:

1. Google Search Console: This is a free tool offered by Google that provides insights into how your website is performing in Google search results. It also alerts you to any potential technical issues with your website that could affect your search ranking.
2. Google Analytics: This is a free web analytics service that tracks and reports website traffic. It can help you understand your audience, measure the success of your SEO efforts, and make data-driven decisions to improve your website’s search ranking.
3. Ubersuggest: This is a free keyword research tool that helps you find keywords to target in your SEO efforts. It provides keyword suggestions and analysis of the competition for each keyword.
4. Moz Local Listing Score: This is a free tool that helps you monitor your online business listings and ensure that they are accurate and consistent across all directories and search engines.
5. Ahrefs: This is a powerful SEO tool that provides in-depth analysis of your website’s backlink profile and keyword rankings. While Ahrefs does offer a free version, it is limited in functionality compared to the paid version.