PCUnlocker offers a paid version, but the allows you to reset the local administrator password on Windows Server 2016. The limitation? It may not work on domain controllers or for full Active Directory resets in the free version.
If you prefer dedicated recovery software, these established open-source tools are compatible with Server 2016: Trinity Rescue Kit windows server 2016 password reset tool free
If you prefer a dedicated utility with a graphical interface or specialized features, these tools are highly rated for Windows Server 2016: PCUnlocker offers a paid version, but the allows
A password reset using third-party tools will not be logged inside Windows. If you are in a regulated environment (HIPAA, PCI-DSS, SOX), document the reset immediately. It will appear as a security event gap. PCUnlocker offers a paid version