Listmonk - Send e-mail campaigns from a powerful dashboard. High performance and features packed into one app.
Tweedle App - Notion is nice but sometimes all you need is an app like Tweedle.
Sendy - Sendy is a self hosted newsletter app that sends emails 100x cheaper via Amazon SES
Tweeticide - Tweeticide – Delete All Tweets is a commercial app that enables you to delete all of your tweets at once.
Mailman - Mailman is free software for managing electronic mail discussion and e-newsletter lists.
Plume - App for writing documents, scripts, books and more.