
Hugo is an open-source static site generator that features fast build times, flexible themes, support for multiple content formats, multilingual websites, live reloading, and an active community. It allows developers to easily create and deploy SEO-friendly and mobile-responsive websites.
Bulma is a free, open source CSS framework based on Flexbox and built with Sass. It's 100% responsive, fully modular, and available for free.
Gulp.js is an old but popular site building tool that automates various repetitive development tasks in web development, such as compiling Sass, minifying JavaScript, and optimizing images.