Rescatux was the standard for grub repair in MBR and EFI systems. It has a ton of tools. Recent updates arent compatible with new machines and the system wont load anymore. If you have a GPU+CPU machine (like a AMD A6 R4) forget to use rescatux.
However if your machine is compatible, use rescatux as it's probably the best tool for repairing boot problems, disk management and thousand of thing more.
Hirens BootCD - Hirens BootCD is a powerful, all-in-one boot disk utility that will help you resolve and make reformatting your computer easily.
Rufus - Rufus is a piece of software that allows you to transform a portable drive, like a flash drive or other USB drives, into a bootable drive that can be used for a variety of purposes. Read more about Rufus.
Ultimate Boot CD - The last Boot CD you'll ever need. You need the Ultimate Boot CD if you want to:
YUMI - YUMI (Your USB Multiboot Installer), is a tool that allows you to boot multiple ISO files from one USB drive.
Finnix - Finnix is a small, self-contained, bootable Linux CD distribution for system administrators, based...
SUSE Studio ImageWriter - Utility for writing raw disk images & hybrid isos to USB keys.