The most easiest email newsletter service. Free for any amount of subscribers, except paid posts(via Stripe). The quickest set up ever. The service provides you a mail address in San Francisco.
A lot of custom settings but Mailchimp has a very difficult UI/UX. Also is paid for 2000+.
A very intuitive UX/UX and quick set up but requires a confirmation email after a user has subscribed. TinyLetter is free as long as you aren't sending emails more than 5,000 contacs.
Another email service + A/B tests, segmentation, pop up forms, key metrics
End the guesswork. Find the best time to send your emails based on your recipient’s characteristics and the type of a company they work for.