There are literally thousands of themes available, on the internet, for WordPress.  Most are themes you will pay for but there are also a few hundred that are free.  WordPress.org has a repository with many of these.  Clicking on “Add New” when in the themes screen will bring up another screen with filters to help you find a desired theme.In this screen enter a check mark in the desired choice and then click on “Find Themes”.  You can also search for a theme if you know the theme name.