European alternatives to Fantastical

Tutanota is a secure email service with a focus on encryption and privacy.

Thunderbird is a free and open-source email, newsfeed, chat, and calendaring client.

eM Client is a desktop email client with calendaring, tasks, contacts, and chat features.

Mailfence is a secure and private email service offering encryption and digital signatures.

Open-source, self-hostable content collaboration platform. File sync, chat, calendar, and more.