What do you want out of a coding monospace font?

- Being easily able to tell the difference between characters that are otherwise similar (such as O vs 0 and l vs 1 vs I)

- No ligatures and no kerning (a monospace font should not have these features)

(The two above are perhaps the most important (and I think are probably already common enough); the below are less important but still might be good to have)

- Bitmap font for on screen, and also scalable fonts suitable for printing

- Versions of fonts for different character sets (such as ASCII and APL and PC), without using Unicode or other unified character sets

- Possibly, glyphs for control characters (if it is PC character set then it already does, since they are graphic characters with the same codes as the ASCII control characters; another alternative if not the PC character set, is to use ISO 2047)

- Visible: tabs, trailing spaces, spaces that are mixed with tabs, line continuation, page breaks (this is more of a feature of the editor or display rather than of the font, although a font might include glyphs specific for this purpose with special character codes)

Wide range of weights (light to bold). Iosevka did a good job of making paper thin to thick sumo.

Sometimes I like to use a very dark theme and crank up the font size. Thick fonts become blinding light. So I need thin variants to dim them down.

This ties into "relaxing". When you zoom in to only ~28 lines on screen you are more focused on the relevant section, present in the moment. Relaxed not worried about the 50+ lines that no longer fit on screen.

Clear distinction between numerals and letters. O and 0, 1 and l, S and 5. Also distinctive punctuation. '.' and ',' are too similar in a lot of typefaces.

How to quantify which font is "best" is a tricky question. I do flip through available programming fonts on occasion just to see if something feels right. A recent favorite is Monaspace Neon from Lettermatic. One detail actually is that I find I like zeros that are noticeably different than an uppercase letter 'O'. In Monospace Neon for example the zero has a dot in the middle.

Not like I need it for coding but technically or graphically I like the idea of fonts that have double with for CJK characters and it all tiles nicely.

I want that it looks good. Nostalgia vibe

Box drawing glyphs that line up correctly.

Easily scannable like Maple Mono

Readability and good looks.