mailbox.org 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.

Posteo is an email service without advertising, with a focus on sustainability and security. They offer webmail, calendar (incl. CalDav), contacts (incl. CardDav). They do not offer to use your own domain and is therefore rather suitable for private users only.

Soverin is a Dutch email provider with a focus on privacy and custom domains. The standard price of the service even contains one domain. Using a personal domain reduces the vendor lockin of the email provider.

Proton Mail is an email provider with a strong focus on privacy based in Switzerland. 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 encrypted - therefore Proton Mail has no way of accessing your private data!

tutanota is an email provider with a focus on security and privacy. Besides email, they also offer calendar and contact management. The biggest feature of tutanota is that data like emails, calendar and contacts are end-to-end encrypted.

This means that not even the provider itself can read the data because they are decrypted only at the client. This also means that only the clients of tutanota can be used to retrieve mails or edit the calendar. tutanota offers clients for the browser, iOS, Android, Windows, Mac and Linux.

Gandi Email is an email service provided by the French hosting/domain registrar company Gandi. They offer their email service for free as long as you register the domain for the email on Gandi.

eclipso is an email provider from Germany. Besides file storage, they also offer calendar and account management including CalDAV and CardDAV. For companies, they offer a service that can be used to send letters and faxes. The servers are located in Germany.

Seeweb Mail is an email provider product of the Italian cloud provider Seeweb.

Raidboxes Emails is the email provider service from the German WordPress hoster Raidboxes.

Migadu is a email provider from Switzerland that only charges per usage (emails sent, storage, ect).

mailfence is a Belgian email provider with a focus on privacy. Besides emails, you can also manage calendars, contacts and files. They offer webmail, calendar (incl. CalDav), contacts (incl. CardDav). mailfence supports organizations that advocate for digital rights with its revenues.

Mailo is a french email provider. They offer webmail, calendar (incl. CalDav), contacts (incl. CardDav).

WEB.DE is a German e-mail provider with a focus on the German-speaking market. They offer webmail, calendar (incl. CalDav), contacts (incl. CardDav).

GMX is a German email provider with a focus on the German-speaking market. They offer webmail, calendar (incl. CalDav), contacts (incl. CardDav).

Inbox.eu is an email provider from Latvia that also offers calendar and contacts management. The plans include a lot of mailbox and file storage. The company behind inbox.eu, Inbokss, is also the producer of the email services inbox.lv, inbox.la, mail.ee and inbox.lt, which are geared more towards the more local market.