GRUB - Multiboot boot loader
Boot Repair Disk - A simple tool to recover access to your Operating Systems. * Easy-to-use (repair in 1 click ! )
EasyUEFI - Manage EFI/UEFI Boot Options & Manage EFI System Partitions & Fix EFI/UEFI Boot Issues
BootIt Bare Metal - BootIt Bare Metal is a boot manager and partition manager software utility.
EasyBCD - EasyBCD is NeoSmart Technologies multiple award-winning answer to tweaking Windows bootloader.
Grub2Win - Safely dual boot Windows and Linux without touching the Windows MBR.