Always great to see new libraries so thanks for contributing to the ecosystem.
Given the domain of your library, you might find the data that is built and managed by the Common Locale Data Repository (CLDR) to be a useful source.
I use the data in a bunch of my libraries and you can find a wealth of reference data in the locale file for English. The format of the data is stable across CLDR releases (which happen twice a year) so its quite a solid foundation.
