A couple more native X11 client implementations:

Common Lisp: https://github.com/sharplispers/clx

Go: https://github.com/BurntSushi/xgb

Any others?

(Looking for implementations of the X11 protocol in $LANGUAGE, not bindings to the C Xlib)

This is what I actually thought the article was going to be about!

Haha, I also expected this.

Now I'm kind of glad you responded in kind because I'd seen python-xlib but not the node one. That sounds like a bit of fun and punishment at the same time.

This what I expected from the title.