less is a dynamic stylesheet language that extends CSS with features like variables, nesting, mixins, and functions. It allows developers to write more maintainable and reusable stylesheets, making it easier to manage complex designs. While Less is a popular choice for styling web applications, there are several alternatives that offer similar or enhanced capabilities. Here are a few notable alternatives:

• cssnano is a CSS minifier that optimizes CSS files for production by removing unnecessary whitespace, comments, and other redundant code. While it doesn't provide the pre-processing features of Less, it is often used in conjunction with other CSS preprocessors to ensure that the final output is as small and efficient as possible. If your primary concern is optimizing CSS for performance, cssnano is an excellent choice.
• postcss is a tool for transforming CSS with JavaScript plugins. It allows developers to use modern CSS features and preprocessors by applying various plugins that can lint, transpile, and optimize CSS. PostCSS can be configured to work similarly to Less, but it offers more flexibility and a wider range of plugins. If you want to leverage the latest CSS features while maintaining compatibility with older browsers, PostCSS is a powerful option.
• sass is another popular CSS preprocessor that extends CSS with features like variables, nesting, and mixins. It is known for its robust feature set and has a large community and ecosystem. Sass provides two syntaxes: SCSS, which is a superset of CSS, and the indented syntax. If you are looking for a mature and widely adopted alternative to Less, Sass is a strong contender.
• stylus is a CSS preprocessor that emphasizes flexibility and simplicity. It allows for a more concise syntax compared to Less and Sass, enabling developers to write styles with less boilerplate code. Stylus supports features like variables, mixins, and functions, making it a powerful tool for styling. If you prefer a more minimalist approach to writing CSS, Stylus might be the right choice for you.

To explore how these packages compare, check out the comparison: Comparing cssnano vs less vs postcss vs sass vs stylus.