I'm mildly skeptical of any shortcuts that are based on "learning habits". I've already gotten enough of user interfaces that move items based on use all the time (The spotify playlist list is the worst offender - playlists move up and down in rank after every use, so there is never any spatial memory, startled every time).

I found the per-directory "suggest-while-typing" history in Fish (and Zsh with the right extension) very intuitive. It speeds up getting around the filesystem, and to common locations tremendously, and of course also remembers regular commands. And it "just works", there is nothing to setup and no commands to remember.

tried fish for some time for the implicit completion but the otherwise excotic nature of the shell has caused me enough headaces to revert to bash and live with C-R

Best of both worlds, fish-like autocomplete combined with bash-compatibility :)