I recall a couple of editors and some tools were kicking around written in B. I would check the GCOS archives, as I believe that for a long time, B was a popular systems programming language for that OS target. B might have been moved to Multics, but I have no memory of seeing it. IIRC, most system programming there was on in its powerful PL/1 dialect or a Fortran/often with a preprocessor like MORTRAN or RatFor, which I did see.
Interestingly, I also have no memory of a B implementation for the PDP-10, which like GE/Honeywell systems, was 36-bit, word addressed. I used BLISS and SAIL on those, if not the assembler.
FWIW: Besides C, B also begat two other languages Eh and Zed, both at Waterloo, Eh I believe, was what the original Thoth system was written, although it might have had some utilities in B; you have to ask someone like Mike Malcom. Since many/most of the 1970s mini's and later micro's, ISAs were byte addressed, the word nature of B (and the fact that the source to Ritchie C compiler came with UNIX), is probably what caused it to have a more limited life.