lkrn - Build a linux kernel bootable file for using with grub/etc...
qemu - Build the required PXE ROM images for app-emulation/qemu
savedconfig - Use this to restore your config from /etc/portage/savedconfig ${CATEGORY}/${PN}. Make sure your USE flags allow for appropriate dependencies
secureboot - Automatically sign efi executables using user specified key
undi - Build a Universal Network Device Interface driver chainloading your existing PXE NIC into iPXE