Sort By Ratings on Product Listing of Magento

Ever wondered what does your customers do to find the best and product from your catalog containing hundreds or thousands of products. 
Well, as a customer purchasing online rely more on the recommendations of other customers. 
Magento provides reviews and ratings module out of the box. Your customers can leave reviews and ratings for the products based on different criteria. These reviews can be useful to you for making the product as per the customer's expectations.
But, by publishing the reviews and ratings also helps the other customers  also to decide the purchase. When there are multiple similar kind of products in your catalog, the ratings will be even more important and useful for the customers.
Magento provides flexibility to sort the products by different attributes, however, sorting by ratings is missing.
Along with full use of review and ratings module, you should consider providing sorting by ratings and rich snippets of reviews.

If you are running your store on the Magento version 1, following product sorting extension for Magento 1 can be useful which is affordable from price point of view.
For the merchants who are running their store on Magento 2 platform, the product sorting extension is available here.