The best replacement for uefi is bios.

The best alternatives to uefi are rated as following:
★★★★★  bios
★★★★★  legacy
★★★  legacy windows 7
★★★  mbr
★★★  legacy boot
★★  ahci
★★  legacy windows 8
★★  efi
★★  csm
★  legacy bios
★  legacy oprom
★  gpt
★  bios mode
★  legacy ubuntu
  legacy mode
  coreboot
  legacy boot mode
  p2
  bios boot mode
  legacy raid

Your alternative for uefi is not listed? Suggest!
Speaking about uefi, one probably shouldn't forget about windows 7.

Other search terms related to uefi and their ratings are:
★★★★★ windows 7
★★★★ mbr
★★★★ gpt
★★ ubuntu
★★ windows 8
★ bios
You have in mind a companion for uefi and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of uefi in all years. Click on graph for more.
uefi
bios
legacy