Gatsby.js is free and opensource Framework based on React. It is a one of the most popular static site Generator that makes easy to build fast and interactive website using React. It is also built on GraphQL (Query Language), so you can query date and display them on your static website any way you want.
Official Website definition: Gatsby is an open source, modern website Framework that builds performance into every site by leveraging the latest web technologies such as React and GraphQL. Create blazing fast apps and website without needing to become a performance expert.