I'm not sure how, exactly, the term typeface is defined, but I think metafont has to be in the running for that title.

https://en.m.wikipedia.org/wiki/Metafont

There are also fonts that exist just to show off variable fonts, like Amstelvar and Decovar. There's another crazy one that starts with an R: Recombinant or something.

I think Noto: https://fonts.google.com/noto