The best replacement for bootloader is bios.

The best alternatives to bootloader are rated as following:
★★★★★  bios
★★★  boot manager
★★  recovery
★★  bootstrap loader
★★  bootloader
★★  recovery android
★  bootstrap
★  root first
★  root
★  fastboot
★  grub
  rooting

Your alternative for bootloader is not listed? Suggest!
Speaking about bootloader, one probably shouldn't forget about arduino.

Other search terms related to bootloader and their ratings are:
★★★★★ arduino
★★★★ fastboot
★★★★ arduino uno
★★★ uno
★★★ flashtool
★★ odin
★★ root
★ linux
You have in mind a companion for bootloader and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of bootloader in all years. Click on graph for more.
bootloader
bios
boot manager