Markdown beyond basic standard HTML

Not only just syntax highlighting in code blocks, or emoji short codes. This can easily be found in

• VSCode or Atom IDE with Markdown Preview Enhanced
• RMarkdown in R language
• GitLab Markdown

Features I love

• Math equation writing with LaTeX
• CSS preprocessor support (e.g. SCSS, LESS)
• External file imports

Of course, all can be exported to HTML for publishing on the web.