Password managers. People will use anything but that: paper, notes app (without any security), using the same password everywhere…

People still use Ubuntu?

I can’t give you any useful advice on the phone/os, but I really think you should keep an old or cheap android phone as a backup. You never know when you are going to absolutely need some app, that is unfortunately only available on mainstream phones (android or iOS).

ncdu: shows how much disk space is used by each directory, can also explore subdirectories and delete files

tig: interactive terminal UI for git with lots of functionality