Ask HN: What are your favorite newsletters?

The author of "HN: Bad For Your Well Being" https://news.ycombinator.com/item?id=6751191 posted links to a few newsletters that aggregate/curate posts on some programming languages. What are your favorite newsletters that provide a similar aggregation/curation function in any topic? Math, art, physics, literature, programming. I think the wider the variety of subjects, the better.