HTML templates are pre-designed and pre-built web pages that can be customized and used as a basis for building websites. They often include common elements such as headers, footers, menus, and content sections, and can be easily edited using HTML and CSS to fit specific branding and content needs.

SCSS is a preprocessor scripting language that extends the capabilities of CSS by adding features such as variables, nesting, and mixins. It allows developers to write more efficient and maintainable CSS code, and helps to streamline the development process by reducing repetition and increasing reusability.

A template or theme refers to a pre-designed layout or structure that provides a basic framework for building a specific type of application or website. It typically includes good design, placeholder content and functional features, allowing developers to customize and fill in the details according to their specific needs.

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.

Pug is a high-performance template engine for Node.js and browsers that enables developers to write HTML templates using a concise and intuitive syntax. It supports a range of features, including template inheritance, conditionals, loops, mixins, and more, and can be easily integrated into a variety of web frameworks and build tools.

RollupJS is a popular and efficient JavaScript module bundler that takes the code from multiple modules and packages them into a single optimized file, minimizing the overall size of the application and improving its performance.