Parallels Workstation is described as '+ Professional-grade Virtualization for PCs:
Simultaneously run a wide variety of Windows versions, Linux distributions, web stacks, database configurations, and multi-tier cloud environments on a single PC with the power and performance you need for web development, QA testing' and is a Virtualization tool in the network & admin category. There are more than 10 alternatives to Parallels Workstation for a variety of platforms, including Windows, Linux, Mac, Web-based and BSD apps. The best Parallels Workstation alternative is VirtualBox, which is both free and Open Source. Other great apps like Parallels Workstation are QEMU, VMware Workstation Pro, KVM (Kernel-based Virtual Machine) and Parallels Desktop.