ProxMox VE

A KVM-based hypervisor, Proxmox provides management through a comprehensive webgui. Based in Germany, Proxmox Server Solutions GmbH provides commercial solutions and support. Even though Proxmox does not mention a free or trial tier in their pricing tables, their docs include information for running Proxmox without a subscription. This only provides access to the no-subscription repository, instead of the enterprise repository, however I ran my homelab on the no-subscription repository for years without any issues. Handily Proxmox does not gate any features behind subscriptions, so you can run Proxmox without a subscription and still have an unlimited number of clusers and cluster members, among all other features. Support with no subscription is limited to their community forums of course.