https://www.pgcli.com/ is an amazing tool. Has autocomplete, Vim mode, and warnings for destructive commands. The REPL experience is amazing as well!

Additionally, postgres's psql CLI supports an rc file, one you can use for awesome configs. Put some time into that as well.

Thank you for this. Looks very promising!

I just came across https://github.com/erezsh/Preql and it seems interesting as well, although not what you are looking for.