Comment by panzi
Indeed I meant these: https://en.wikipedia.org/wiki/Symbols_for_Legacy_Computing
I use them in some tiny hobby projects like these:
https://github.com/panzi/progress-pride-bar
https://github.com/panzi/bad-apple-terminal
https://github.com/panzi/js-unicode-bar-chart
https://github.com/panzi/js-unicode-plot
Reading the flags one: Unscii has font coverage, if you want to try that out on the emulators whose fonts were problems.
* https://news.ycombinator.com/item?id=43812026