Not particularly high-level, but representing common TUI designs and usage patterns on Unix: Slrn, Mutt, Ncdu.
https://en.wikipedia.org/wiki/Slrn
https://en.wikipedia.org/wiki/Slrn
Thanks for listing it.
It's especially great if the server is out of disk space and/or the server is under too heavy a load to keep an SSH connection going; you can investigate what's clogging up space (usually logfiles gone awry) and clean up accordingly.
It's one of the default utilities I have installed on my servers for a very good reason and it's helped out countless times over the past few years for hobby servers of mine (aka the ones where "scaling it up" isn't an option because the budget is constrained by it being a hobby).