QEMU - QEMU (short for "Quick EMUlator") is a free and open-source hosted hypervisor that...
Grub2Win - Safely dual boot Windows and Linux without touching the Windows MBR.
Portable Virtualbox - Portable-VirtualBox is a free and open source software tool that lets you run any operating system from a usb stick without separate installation. Installation instructions. Download and run Portable-VirtualBox_v5.
GRUB - Multiboot boot loader
bochs - Bochs IA-32 Emulator provides a virtual PC that can run operating systems such as Windows, Linux, and BSD.
EasyUEFI - Manage EFI/UEFI Boot Options & Manage EFI System Partitions & Fix EFI/UEFI Boot Issues