CISCO Packet Tracer Software
It is a simulator tool that is used to design Networking, Cyber security and the IOT base labs. It allows you to design complex lab without need of hardware equipment.
VMware Workstation is used to install one desktop computer to run multiple OSs without installing them on your PC.
Server (2012,2016,2019) versions in ISO format
Windows Server is a server operating system is specifically developed to serve as a platform for running networked applications.