RMPrepUSB!

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.

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.

You can prepare an Easy2Boot USB drive using Windows or linux.Then add all your payload files (.iso, .img, .ima, etc.) to one of the folders on your USB drive (e.g. \_ISO\MAINMENU folder) by drag-and-drop at any time. A new menu is automatically created each time you boot from it.Works with 99% of linux liveCD ISOs and supports Windows Install ISOs too! Install from an unmodified XP ISO file to a RAID/AHCI/SATA system (no need to nLite the ISO first).The USB drive can be formatted as FAT32 or NTFS (or exFAT, ext2/3). UEFI booting of linux and Windows is supported by creating .imgPTN partition image files. Boot to any number of Windows Vista/7/8/MSDaRT and linux UEFI OS's. »

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/ )

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

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

HP USB Disk Storage Format Tool utility will format any USB flash drive, with your choice of FAT, FAT32, or NTFS partition types. You can also make the disk bootable by specifying a file location.

USBWriter is tiny Windows tool that lets you write an image file directly to an USB drive. It requires no installation and depends on no bloated framework, it's just a little program that you may put on your desktop.

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

ISO to USB is a free and small software that can burn the ISO image file directly to the USB drives, these USB drives include USB flash drives, memory sticks and other USB storage devices, it also supports to create a bootable USB disk with Windows operating systems.

Optical drives are rapidly disappearing from our computers of all kinds, and consequently installing operating systems from USB flash disks is becoming increasingly popular. ISO images of the ROSA Linux distribution were originally intended for burning to DVD disks, but they can as well be written to flash disks which would allow you to boot from them and launch the Live system or start installation. There is no standard tool for writing images to flash disks, everybody uses what he or she likes. In ROSA the command line tool dd was traditionally recommended for performing this kind of job. However, it can hardly be called user-friendly, and most users would feel at least some discomfort, if not terror, using it. For Windows users the situation is even worse. Granted, there is a dd port for Windows, but it happened to have serious bugs which prevent the resultant flash disks from working properly. All this led to the solution of developing our own tool, ROSA Image Writer. »