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?]
I’m a sucker for jetbrains Mono when I need a monospaced font. It just looks nice to me.
I use fantasque for my monospace, fira sans for my work horse ui font, and Garamond for my “someone wants to display serifs for some reason”
Ubuntu fonts works pretty good for me as a general UI font tbh. In text editors I prefer mononoki over monospace, it’s a bit prettier IMO, although in terminal I use terminus because pixel fonts are cool.
Dejavu, Liberation, & Noto are all pretty common.