Jujuu
Listmonk is a self-hosted, high performance one-way mailing list and newsletter manager. It comes as a standalone binary and the only dependency is a Postgres database.
ntfy (pronounced notify) is a simple HTTP-based pub-sub notification service. It allows you to send notifications to your phone or desktop via scripts from any computer, and/or using a REST API. It's infinitely flexible, and 100% free software.
Roundcube webmail is a browser-based multilingual IMAP client with an application-like user interface. It provides full functionality you expect from an email client, including MIME support, address book, folder manipulation, message searching and spell checking.
All-in-one secure chat app for teams, friends and organisations. Keeps conversations in your control, safe from data-mining and ads. Talk to everyone through the open global Matrix network, protected by proper end-to-end encryption.