There's also Bindery, a JavaScript library for book creation which also leverages the print-to-PDF feature built into modern browsers: https://evanbrooks.info/bindery/

On top of that and the in-browser Markdown renderer Markdeep, I've built a tool for typesetting undergraduate theses: https://github.com/doersino/markdeep-thesis/

And, coincidentally, just a few days ago I've written a blog post about controlling the settings in Chrome's "Print" dialogue with CSS (other browsers don't support many of the relevant features): https://excessivelyadequate.com/posts/print.html