[caspar]

2x2 pixel font is probably impossible[1], but with a few more pixels of width someone made a surprisingly readable 2-pixel-high font: https://www.reddit.com/r/PixelArt/comments/1myh81x/2px_high_...

Released by the author at https://joefatula.com/twoslice.html

[1]: unless you use multiple glyphs for a char. Or maybe it'd be possible to interpret if the glyph-to-char mapping pattern was very carefully thought out..