Unifont seems very useful. Not pretty but definitely legible.

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FWIW, I ran across this the other day: "4x4 ASCII Font"

> Small fonts have always been fascinating to me, so I decided to make the smallest font possible, which turned out to be 4x4 pixels per character. The font covers the entire range of visible ASCII characters, and most are immediately recognizable.

https://simplifier.neocities.org/4x4.html

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For display from small machines I keep going back and forth between simple memory-mapped raster screens vs. emitting a stream of, say, SVG to an external "display processor" (following the "Wheel of Reincarnation": "On the Design of Display Processors" http://cva.stanford.edu/classes/cs99s/papers/myer-sutherland... )