There are some great rating plugins out there in the WordPress universe. All of them have their own approach to allowing users to rate a post, comment or other content type. I had a need for a plugin which added a rating interface in a more light weight and streamlined way. Custom Ratings was created to fill this need.
As usual, you can find this in the WordPress plugin repository and read a more detailed description on the plugin page: https://wordpress.org/plugins/custom-ratings/.