MultiBoot USB
This is a project that contains a collection of GRUB files and scripts that will allow you to create a pendrive capable of booting different ISO files.
RancherOS is a tiny Linux distribution that runs the entire operating system as Docker containers. This includes system services, such as udev and rsyslog. RancherOS includes only the bare minimum amount of software needed to run Docker. This keeps the binary download of RancherOS very small. Everything else can be pulled in dynamically through Docker.