For what it's worth, after a bit of research [1], I discovered Commodore Basic 2.0 had simple FOR loops (which I think I used and forgot), and the ability to create functions which encode a single one-variable mathematical expression (which I don't think I ever knew about).
I forget what the name was, but I used a Microsoft Basic on the IBM PC platform a few years later which was light years better than the C64 Basic. Still gave it up ASAP after learning C, mind you.
[1] https://www.c64-wiki.com/wiki/DEF