You can view a keyword's top sites by going to SEO > Competition and doing an analysis. You have the option to display the top 3, 10 or 20 sites in Advanced Settings.
After the results are generated, please go to the Report column (the last column) and click the "View details" link.
It will show you the top sites and valuable ranking data about them, such as Domain Authority, on-page optimization, backlinks, and social signals.
You can then save the details as an HTML file if you wish to refer to them later or share your findings with others.