I absolutely love these sorts of things :).

I assume we are all familiar with User Inyerface? https://userinyerface.com/

As St IGNUcious said, proprietary software is the sin. Using vi the penance.

With projects like these, I’m always torn between thinking that it’s cool it’s possible, and horror that someone somewhere will try to use this in production code.

The only one I really remember is Trogdor, but in order to keep it in my heart, I am a proud owner of Trogdor!!: The Boardgame

Depending on the complexity, there’s also abbrev-mode: https://www.gnu.org/software/emacs/manual/html_node/emacs/Abbrevs.html

There’s a fork of Openboard that is trying to update it, but AFAIK, it’s not published anywhere yet: https://github.com/Helium314/openboard