Radix Nubes

If VMs aren't important to you, much of the industry has gone to containers using Kubernetes as the resource management layer. Performance of containers tends to be better than VMs, but you are sacrificing the fully functioning OS... if that's important. https://kubernetes.io/

Mesos is an option that (I believe) dispenses with the traditional IaaS cloud infrastructure model and simply presents your cloud as a pool of resources for executing jobs. This simplifies it for home/small-business use. However, that means the API may be unfamiliar to most with an AWS or OpenStack background. https://mesos.apache.org/

OpenStack is a good starting candidate because it can run anything. This may not be important to some (most) users, but to people who need to run VMs to have a full OS available for testing (is there any other reason), it's one of the few options. IaaS and PaaS are particularly useful for experimenting with new cloud architectures. That would be difficult to do without a driver like OpenStack. https://www.openstack.org/

Notes about progress toward a functioning OpenStack cluster. https://joshfuhs.com/openstack-single-node-options/