Hi everyone. I been using FreeMono around 6 months so far anywhere on my system and it's my favorite font, however I'm using my own thickened version because the standard FreeMono font is unreadable on high DPI screens.
With 176 DPI, 1080p resolution on a 12.5" screen, the font appears on screen very thin, combined with proper anti-aliasing, slight hinting, properly set DPI values for all GUI toolkits.
My solution was to increase the font weight by 20% (including the serifs) for the regular and italic versions of FreeMono (via fontforge). It's highly readable, and it doesn't confuse with the bold version at all, which is way thicker.