Mostly finished: Latin, Cyrillic, Greek, Kana.

X-height tends to be about 5px, with maximum 2px descenders and 2px ascenders. Cap height is 7px. Width generally 4px for lowercase and 5px for uppercase but depends on the letter, spacing usually 1px. Han characters aren't very doable at this resolution. including them is mostly for fun.

Update: Removed hangul and han characters to avoid mismatched writing (there would still be pixel kana alongside nonpixel han characters but hopefully that wouldn't be as jarring as having only some han characters be pixelated)

Based on https://fontstruct.com/fontstructions/show/2155925/threebyfive-6 but extended to 5x5, so cyrillic greek and kana are more readable.

Crisp at sizes multiple of 4.5 (9)

Based on a pixel pixel font I made a while back, trying to stick to the limitation of a fictional text rendering system* TL;DR 3x5 letter bodies with limited space for diacritics. Font is crisp at sizes multiple of 4.5**,  really it's just a latin font but there's some experimental cyrillic, greek, and katakana which is kinda messy.

*Text would be rendered on a grid made up of alternating blank/diacritic lines (made of 3x2 boxes) and letter body lines (3x5 boxes). Each box is separated by 1 pixel in which glyphs cannot be drawn on. Diacritic boxes can be used to display a diacritic on either the letter above or below them; a limitation of this system is that this sharing of diacritic spaces could cause ambiguities.

**Weird number but that's how i got the line spacing I wanted. In the fictional system mentioned above, a technical limitation would be that the same slots are shared for diacritics above and below, causing them to overlap if a letter with a lower diacritic was on top of a letter with an upper diacritic.