In the mid-90s, I used Byron Rakitzis' implementation of Plan 9's rc shell. I used it at work on SunOS 4.x. It was most excellent when I was able to have a meticulously-arranged, bespoke environment of startup and utility scripts around it. The scripting/programming language it incorporates is elegant, and simple, yet powerful, just like a utopian sort of environment envisioned by the Plan 9/Bell Labs folks.

Chris Siebenmann still uses rc, to the best of my knowledge. https://utcc.utoronto.ca/~cks/space/blog/unix/WhyISwitchedTo... He's not a poster to HN, AFAIK, but his blog is frequently featured here. I'm not sure whether he's amenable to sharing his configuration and utility scripts, but if you're at all interested, it's worth asking him, I would suppose.