Install Disk Creator!

The Reliable USB Formatting Utility

UNetbootin (Universal Netboot Installer) is a cross-platform utility that can create Live USB systems and can load a variety of system utilities or install various Linux distributions and other operating systems without a CD.

Clonezilla is a free software disaster recovery, disk cloning and deployment solution.

DiskMaker X (formerly Lion DiskMaker) is an application built with AppleScript that you can use with many versions of OS X/macOS to build a bootable drive from OS X/macOS installer program (the one you download from the App Store). As soon as you launch the application, it tries to find the OS X Install program with Spotlight. Then, it proposes to build a bootable install disk and make it look as nice as possible. It’s the easiest way to build an OS X/macOS Installer in a few clicks! Then you can use the Install drive to fully re-install the OS on a freshly formated drive, or install it on your many Macs without re-downloading the full installer. »

DriveDroid allows you to boot your PC from ISO/IMG files stored on your phone.

android_usb_msd - Better and open source replacement for DriveDroidA helper application to set the Mass Storage Device gadget up in Android kernels

There are different ways to create a multiple Windows bootable USB stick. But most of them force you to perform mandatory disk formatting or scare with incomprehensible interfaces with many options. It can make you waste a lot of time understanding what to do and selecting important files and their subsequent saving on hard drive…