The best replacement for initramfs is initrd.

The best alternatives to initramfs are rated as following:
★★★★★  initrd
★★★  ramdisk
★★  squashfs

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

Other search terms related to initramfs and their ratings are:
★★★★★ kernel
You have in mind a companion for initramfs and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of initramfs in all years. Click on graph for more.
initramfs
initrd
ramdisk