Google Sans Text, Cabin, Fira Sans, Roboto, Noto

For monospaced Jetbrains Mono, Fira Code, Iosevka

Dejavu.

I really like CaskaydiaCo[d|v]e.

No clue, the default one, in MX Xfce I think it's noto

MathJax Sans Serif

Not common, but Modern DOS is a great nostalgic family of pixel-oriented fonts for terminals and such.

I use Terminus (ter-112n) for TTY, Source Code Pro for terminal emulators, and DejaVu, Liberation, and Noto for others

Taking a quick glance at the font packages I have installed, I find the Liberation family, Freefont, the old MS core fonts, a couple of Bitstream Vera Sans variations (including Deja Vu), and the ancient URW fonts, plus a couple of CJK-specific fonts, since I need those characters just often enough for their absence to be noticed.

Freefont has decent coverage of what was in Unicode as of ten years ago, and so in combination with the CJK specialty fonts covers most common writing systems worldwide. I'm not particularly concerned about things like Anatolian hieroglyphs, a couple of hundred less-common emoji, or the Bitcoin symbol being missing.

I like the new intel mono, and ubuntu for non-mono.

The default font in the web browser on Ubuntu look bad. Different length between the letters and size

Most of the documents I produce are converted to PDF or printed, so I use Nimbus Roman or Nimbus Sans (I believe). I do use Open Dyslexic font

For UI I really enjoy Inter, although Ubuntu, Roboto and IBM Plex Sans are also nice

For terminal I use Hack, although Source Code Pro is nice

I use IBM Plex Sans and IBM Plex Mono

I use whatever the default is for my desktop environment and for terminal I always go for Source Code Pro.