Mine would be Cassidy William's newsletter:
https://tinyletter.com/cassidoo. It's free, but there was a few newsletters where she linked her Venmo/Paypal in case people wanted to support, and I contributed during that time. She's since removed those from the letters for whatever reason. This newsletter is great on a Monday morning because it's light and has some interesting/cool links in it.
Another great one would be Kent C Dodds' newsletters: https://buttondown.email/kentcdodds. Kent is highly active in the React/JS/OS community and he's a super great guy. Same deal here, its free but you can choose to support, which I do from time to time. His newsletters are focused on JS/React and are a bit more dense, but they're interesting.