Universal USB Installer!

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.

Etcher is a free and open-source image burner with support for Windows, OS X and GNU/Linux. It makes USB and SD card image burning as simple and fast as possible.

YUMI (Your Universal Multiboot Installer), is the successor to MultibootISOs. It can be used to create a Multiboot USB Flash Drive containing multiple operating systems, antivirus utilities, disc cloning, diagnostic tools, and more. Contrary to MultiBootISO's which used grub to boot ISO files directly from USB, YUMI uses syslinux to boot extracted distributions stored on the USB device, and reverts to using grub to Boot Multiple ISO files from USB, if necessary.

LiLi USB Creator is a free software for Windows that allows you to create a bootable Live USB key with a Linux on it.

MultiBootUSB is a software to create multi boot live Linux on a removable media i.e USB disk. It is similar to UNetbootin but many distros can be installed, provided you have enough space on the disk. MultiBootUSB also provides an option to uninstall distro(s) at any time, if you wish.

Multisystem is an awesome tool created by LiveUSB.info, that works similar to our Windows based MultiBootISOs USB creator, but was created for use within Linux. It also uses Grub2 instead of Grub Legacy, and can be run from within Ubuntu Linux to create a Custom Multiboot UFD containing your favorite Bootable Live Linux Distributions. (via http://www.pendrivelinux.com/multiboot-create-a-multiboot-usb-from-linux/ )

WinSetupFromUSB is a Windows program, which prepares multiboot USB flash or fixed disk to install any Windows versions since 2000/XP, boot various Linux and *BSD flavors, as well as many Windows, Linux, DOS based and other utilities. Since version 1.1 program can create USB disk with Windows versions which support (U)EFI (Vista x64 SP1 and later x64 versions), which USB disk can be used in both (U)EFI and Legacy BIOS modes.

SARDU (short for Shardana Antivirus Rescue Disk Utility) creates a multiboot all-in-one USB drive, CD or DVD for free (personal and non commercial use). Hard disks, external hard disks and all removable media are supported.The bootable device can include comprehensive collections of antivirus rescue cd, utilities and popular live distributions of Linux. Windows PE can also be included, as well as recovery disks and install media for Windows XP, Windows Vista, Windows Seven and Windows Eight.The multiboot USB supports and manage USB stick, pendrive, hard disks and all removables media. »

LiveUSB Install is a free software for GNU/Linux and Windows.

Mac Linux USB Loader is an application that allows you to create bootable USB drives containing a Linux distribution that can boot natively on Apple's Macintosh computers using their EFI system, regardless of whether or not the selected distribution has UEFI support.

Utility for writing raw disk images & hybrid isos to USB keys.

The liveusb-creator is a cross-platform tool for easily installing live operating systems on to USB flash drives.

XBoot is a easy-to-use utility for creating Multiboot USB/ISO.You may have seen many bootable ISO files like Linux live CDs , Antivirus rescue CDs etc. XBoot can combine these ISO files in to one Multiboot ISO file or create Multiboot USB in just few clicks. Simply Drag and drop ISO files in to XBoot and click Create ISO or Create USB button.