What are some newsletter niches/topics that you would be interested in reading?

I read everything about product management and email marketing, but I subscribe only to the experts in the area I think, it does not matter which niche, you just need to have a deep understanding about what you're talking about and be able to explain the topic in the understandable way

I write a newsletter about anti-success stories + lessons from failure for founders: sunsetclub.substack.com