Mod Name: Noto Sans Font Replacer
Manual Download: Install
Description: Author of font: Google
License: SIL Open Font License
City of Heroes two main True-Type fonts: Montreal-DemiBold and Montreal-Heavy. Are nearly 30 years old and are missing quite a bit of modern character/glyphs support. They also make it impossible to tell lower case L 'l' from uppercase i 'I' which, for some people, that's a feature as far as names go but, I find that annoying when trying to type out someone's name for team invites.
So, after lots of testing of various different fonts and styles and weighting in their pros and cons, I decided to replace those two fonts with Noto Sans Bold (700) and Noto Sans Black (900)
These two fonts are quite close to the original in-game fonts with some minor differences but also include small amounts of serifs so that you can better tell apart "i I l L". They are also very readable, just like the original in-game fonts. There is some minor sizing issues in-regards to the UI in how it handles these fonts but nothing terrible. How the UI uses the fonts is mostly hard-coded so besides using the font slider in the options window, you can't really do anything about the minor sizing issues.
Additional links about Noto Sans: