GRUB - Multiboot boot loader
EasyBCD - EasyBCD is NeoSmart Technologies multiple award-winning answer to tweaking Windows bootloader.
EasyUEFI - Manage EFI/UEFI Boot Options & Manage EFI System Partitions & Fix EFI/UEFI Boot Issues
Grub2Win - Safely dual boot Windows and Linux without touching the Windows MBR.
Grub Customizer - Grub Customizer is a graphical interface to configure the GRUB2/BURG settings and menuentries.
BootIt Bare Metal - BootIt Bare Metal is a boot manager and partition manager software utility.