The Virtual Machine Manager (virt-manager) remains one of the leading open-source solutions for managing virtual machines using open-source software. Virt-manager primarily targets Linux with KVM, Xen, and LXC support, but now it can also interface with Bhyve.
The Bhyve BSD hypervisor is a legacy-free hypervisor that relies upon modern CPU virtualization features and VirtIO drivers. Those unfamiliar with this new BSD hypervisor can visit Bhyve.org.
With this Git commit there is now Bhyve support within virt-manager, but for at least the time being the support is disabled by default.