[hazeii]

Generally anything low res is hand-designed on a pixel by pixel basis (whether monochrome or limited colours). For fonts the lowest legible is 5x8 (depending of your definition of 'legible', e.g. the alphabet as printed on a seven-segment display).

You could look back at early graphics fonts/icons, e.g. early X11 or after that Mac and Windows for inspiration. Also graphics LCD displays (e.g. one or two lines of 16 chars) and then there's the BBC Microbit with its 5x5 display - lots of creative stuff there, the stock demo it comes with does text and graphics (and the code is online).