I absolutely love these sorts of things :).

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

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

I wish this was exaggerated, but it isn’t at all. Every time I try to learn Haskell, I end up in some tutorial: “You know how you sometimes need to represent eigenvectors in an n-dimensional plane with isotonically theoretical pulsarfunctions? Haskell types make that easy!”