Or any other concatenative or stack-based programming language. And Agda and Idris and other dependently typed languages I feel deserve to be on this list. There's also Qi/Shen. Of course various assemblers, too. And logic languages, like Prolog, Datalog, kanren. And then...

In short: every time I thought I know "most" of what there is to know about something I soon discovered that I was wrong, and that "something" was a vast area which I didn't really explore at all except for a tiny little fraction of my immediate surroundings.