pfSense is an open source firewall/router computer software distribution based on FreeBSD.
openmediavault is the next generation network attached storage (NAS) solution based on Debian Linux.
Unraid is software for storing and managing digital files on a mass-storage server. It is an embedded Network Attached Storage (NAS) server operating system.
Syncthing is a free, open-source peer-to-peer file synchronization application. It can sync files between devices on a local network, or between remote devices over the Internet.