Kinto : Kinto is a lightweight JSON storage service with synchronisation and sharing abilities.
SimpleLogin : With email aliases , you can be anonymous online and protect your inbox against spams and phishing. Open-source.
Cachet : Beautiful & simple service statuses. The open source status page system, for everyone.
CryptPad : CryptPad is the Zero Knowledge realtime collaborative editor.
Encryption carried out in your web browser protects the data from the server, the cloud ...
Zulip : Powerful slack-like open source group chat