[anthk]

That's what I tought. Even Miliforth lacks a proper complete integer based stack. From that and a few primitives, you can bootstrap a Forth.

On Lisp, Sectorlisp it's interesting; but the ones from https://t3x.org can do far more, even if they are not bootable per se. But T3XForth can, and it's highly usable.

EForth under SUBLEQ it's like that too.

Instead of "Boot sector languages", I'd pursuit a 386 compatbile language being able to fit in a floppy. T3XForth does, and tons more, because the T3X author made eiher standalone ones, or DOS and CP/M 2.2 ports.