Hi, NoMachine gives you access to the physical display of the remote OS (physical or virtual machine). However, it is not a hypervisor, but you can install it on one since it works out-of-the-box with solutions such as VMware, Virtualbox etc etc. If you have a computer running, for example, 2 separate virtual machines, you could install the free version of the NoMachine on both of them. From the connecting client you would be able to connect to both as separate NoMachine sessions.
Additionally, there is the Terminal Server range (Linux only) which lets you run multiple individual Linux desktops and or applications on the same host.