While I enjoy using
Roboto Mono
as a general purpose monospace typeface, while coding I much prefer to use
Fira Code
. I don't use it for its added ligatures though; I turn those off. I use it because it has additional weights not present in Mozilla's official
Fira Mono
font. I personally use the 'light' weight in my editor.
https://github.com/tonsky/FiraCodeMozilla really did an incredible job creating a type with such elegant form and effective function. The 'i' and 'j' and 'l' are even more distinct than some fonts explicitly designed only for use by programmers while still having character and charm. I would suggest you take a look at it if it isn't already familiar.
https://mozilla.github.io/Fira/What font does lain use for programming?