Bootstrap is the most popular CSS Framework for developing responsive and mobile-first websites.

Less CSS is a dynamic stylesheet language that extends the capabilities of CSS, allowing developers to write cleaner, more modular, and reusable stylesheets with features like variables, mixins, and nested rules.

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.

Stylelint is a modern linter for CSS that helps you avoid errors and enforce consistent styling conventions. It provides rules for detecting errors and warnings, and can be configured to match your specific project's requirements.