Iosevka Charon is a quasi-proportional font excellent for technical writing and dense UI. Iosevka Charon Mono is a true monospace font tuned for coding and terminal use. These font families are unique derivatives of Iosevka (an open source font project) by be5invis; built in a manner that makes the resulting fonts Google Fonts compliant.
To contribute, please see github.com/jul-sh/iosevka-charon.