mailbox is a German email provider. It offers webmail, calendar (incl. CalDav), contacts (incl. CardDav). Their server are CO2 neutral and they also have a video call feature. In the bigger plans it is also possible to use a custom domain.

Proton Mail is an encrypted email service offering end-to-end encryption, protected by strong Swiss privacy laws. It was founded by scientists at the CERN with the goal of protecting the privacy of it's users. The servers are located in Switzerland and the data is end-to-end encrypted - therefore Proton Mail has no way of accessing your data. It’s free to start, ad-free, and designed to keep your communications private without surveillance, ads or tracking.