Rescatux - Rescatux is a GNU/Linux rescue cd (and eventually also Windows) but it is not like other rescue...
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
Finnix - Finnix is a small, self-contained, bootable Linux CD distribution for system administrators, based...
EasyBCD - EasyBCD is NeoSmart Technologies multiple award-winning answer to tweaking Windows bootloader.