Listmonk - Self-hosted newsletter + mailing list manager.
news-api - Go newsletter API backed by DynamoDB.
Mailbrew - Receive the best content from the sites and apps you love in beautiful, automated, newsletters.
Unreadit - Curated weekly newsletters.
On Being a Good Newsletterer - Notes and tips on how not to be a newsletter.
Sendy - Send newsletters, 100x cheaper via Amazon SES.
Digester - Allows you to get updates when you want them.
Buttondown - Small, elegant tool for producing newsletters.
Newsletter Stack - Discover curated newsletters to help you learn about anything.
Lovecroft - Minimal mailing list manager for static sites, with a simple JSON API.