[QUESTION] The most comprehensive and user-friendly source of article metadata in RIS format

[MrChebur]

It's not an bug report, it's a question. Redirect me to another place suitable for discussion and questions if I'm in the wrong place.

What is the most comprehensive and easy-to-use source of metadata about scientific articles that you use to retrieve data in RIS format?

I am currently using MDPI data. The data can be automatically downloaded using browser robots.

I also know about the huge database https://docs.openalex.org. However, if I understand correctly, it does not contain data in RIS format.