Just gave JetBrains mono a spin. I like the design; a bit plain but pretty readable. I had to go in to FontForge and fix what I felt were some issues with the font:
* I prefer a stroke instead of a dot in to 0 (zero)
* While JetBrains mono has an alternate form with a 0 stroke, the stroke is too thin.
* The smart quotes, such as “” look too much like each other. I edited them to give the font Verdana-style smart quotes (where “ and ‘ point to the left)
* The “c” looks too much like “o”. I have opened up the bowl in c so it’s distinct from “o”.
* I aggressively subsetted the font to have only English, Spanish, and some basic typography (smart quotes, em dash, bullet, right arrow). This reduces the size, which means I could make it a webfont in the future.
