Information on religious, ethnic, and cultural celebrations:
Religious holidays of the world: https://study.soas.ac.uk/religious-holidays-of-the-world/
Religious Holidays 101: Quick-start Guide to Learning about Holidays Beyond Christmas by Emily Hamer
Ethnic Celebrations
https://www.georgiaencyclopedia.org/articles/arts-culture/ethnic-celebrations/
Cultural Holidays & Heritage Celebrations
Intercultural Student Affairs by Emerson College
American Holidays > Ethnic & Religious Observances by U.S. Diplomatic Mission to Germany
https://usa.usembassy.de/holidays-ethnic.htm
Videos:
Video: Northern city celebrates interfaith 'Holiday of Holidays'
Video: Most Celebrated Holidays
https://youtu.be/n7ZLZjjDEGo
Video: Diwali - Festival of Lights | National Geographic
Video: Winter Celebrations Around the World
https://youtu.be/V8L4LjqOKmE
The New York Times has a related article “A Look Inside New York’s Swirling Kaleidoscope of Faiths”
https://www.nytimes.com/2022/12/15/nyregion/world-religions-new-york-city.html?smid=nytcore-ios-share&referringSource=articleShare