Nextcloud

Syncthing is an open source peer-to-peer file synchronisation tool.

Web-based operating system designed to be feature-rich, exceptionally fast, and highly extensible.

File management and sharing system, supports multiple storage providers.

File hosting and sharing solution primary for teams and organizations.

All-in-one solution for saving, synchronizing, viewing, editing and sharing files, calendars, address books and more.

Unison is a file-synchronization tool for OSX, Unix, and Windows.

File Sharing and Collaboration Platform.

Collaboration suite with real-time messaging, rich text pages, file management, and dynamic databases - built for offline work (alternative to Slack, Notion).

Minimalist JSON storage service with synchronisation and sharing abilities.

Secure and private space online where you can store, share and view your photos, videos, music and documents. Also includes a calendar, news feed, task lists, chat and email client.

Turn any web server into a powerful file management system and an alternative to mainstream cloud storage providers.