GRUB - Multiboot boot loader
Grub2Win - Safely dual boot Windows and Linux without touching the Windows MBR.
EasyBCD - EasyBCD is NeoSmart Technologies multiple award-winning answer to tweaking Windows bootloader.
Grub Customizer - Grub Customizer is a graphical interface to configure the GRUB2/BURG settings and menuentries.
U-Boot - Das U-Boot (the Universal Bootloader) and Embedded Linux
EasyUEFI - Manage EFI/UEFI Boot Options & Manage EFI System Partitions & Fix EFI/UEFI Boot Issues