Liberation Mono is not bad. Sadly, Liberation Sans is a no-go because it lacks crossbars on the capital "i". Such an annoying failing of so many sans fonts.
Some fonts like Arial are bad at this, capital "I" and lowercase "L" look the same. Calibri and Liberation sans both have slight differences, but not enough to not be confusing. Some fonts like Open Sans have crossbars on capital "I", which solves this problem. But that's not the only solution, fonts like PT Sans have a different looking lowercase "L" which is different enough not to cause confusion. Then again, technically you could also run into issues with the vertical line symbol "|".
Also, PT Mono is a nice font, but has issues with a small full stop symbol at smaller sizes (not as pronounced as Liberation Mono, annoying): https://en.wikipedia.org/wiki/PT_Fonts
Thanks! I compiled a list of sans-serif fonts with acceptable capital "i" and zero/O distinction a while back... but don't have it on hand. But it's a lot faster to go to fonts.google.com, select sans-serif, and change the example text to "Does this have a proper I and O and 0" and start scrolling!
