awsome-holidays
A curated list of awesome holidays libraries
Worldwide
https://github.com/commenthol/date-holidays [Javascript]
https://github.com/dr-prodigy/python-holidays [Python]
https://github.com/azuyalabs/yasumi [PHP]
Only Japan
https://github.com/holiday-jp [Elixir | Javascript | C# | Java | Ruby | PHP | GO | Swift]
https://github.com/LUXEYS/holiday_jp-python [Python 3]