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.
Grub2Win - Safely dual boot Windows and Linux without touching the Windows MBR.
Hirens BootCD - Hirens BootCD is a powerful, all-in-one boot disk utility that will help you resolve and make reformatting your computer easily.
EasyBCD - EasyBCD is NeoSmart Technologies multiple award-winning answer to tweaking Windows bootloader.
Finnix - Finnix is a small, self-contained, bootable Linux CD distribution for system administrators, based...
EasyUEFI - Manage EFI/UEFI Boot Options & Manage EFI System Partitions & Fix EFI/UEFI Boot Issues
Ultimate Boot CD - The last Boot CD you'll ever need. You need the Ultimate Boot CD if you want to: