Apps Related to CalDAV and CardDAV Support

Microsoft Calendar, part of the Outlook suite, is a robust online calendaring platform designed for scheduling, organization, and collaboration. It allows users to manage appointments, events, and tasks effectively, integrate with other services, and share schedules with others.

Etar is a free and open-source material design calendar application for Android, prioritizing privacy and a clean user experience. It focuses on core calendar functionalities like event management and reminders, offering data export/import and syncing capabilities without ads or excessive features.

Kopano is a versatile open-source groupware suite offering email, calendaring, contacts, and online collaboration tools for businesses and organizations. It provides flexible deployment options, including on-premises and hosted solutions, with strong focus on data privacy and security.