For a long time, I’ve just put on DejaVu fonts and been done with it. Generally good enough Unicode coverage for me. But I know it’s been years since DejaVu’s been updated, and I wonder what’s very common today.
[As for the terminal, I’m guessing it’s usually still the standard fixed Unicode fonts?]
Ubuntu / Ubuntu Mono are my favorites.
I use Fedora, but I still install Ubuntu font because I prefer it lol