Nextcloud Drive is an open-source file storage and synchronization platform that can be self-hosted. It lets users keep control of their files while providing cloud-style access and collaboration.

ownCloud is an open-source file synchronization and sharing platform that can be self-hosted. It provides cloud storage features while allowing organizations and individuals to keep their data on infrastructure they control.

Proton Drive is an encrypted cloud storage service from Proton. It provides secure file storage, synchronization, and sharing with a focus on privacy.

Seafile is an open-source file synchronization and sharing platform designed for self-hosting. It provides efficient file syncing and collaboration while keeping storage under your control.

Sync.com is a cloud storage and collaboration service focused on privacy and secure file sharing. It provides synchronization and sharing across devices for individuals and teams.

Tresorit is a cloud storage and collaboration service built around end-to-end encryption. It provides secure file storage, sharing, and collaboration for individuals and organizations.