[rkharsan64]

There's also this font that uses OpenType Contextual Alternates to create sparklines from text: https://aftertheflood.com/journal/the-worlds-first-code-free...

[boffinAudio]

Alas, the .zip file containing those fonts is no longer accessible.

Along similar lines, the absolutely delightful FF Chartwell has sparkline capabilities, plus a lot, lot more to boot (and it actually predates After-the-Floods attempt by half a decade):

https://www.vectrotype.com/chartwell