PXE Knife is a set of utilities modeled after Ultimate Boot CD. It is designed to work with the syslinux boot stacks and was specifically designed for use with PXE (although it's configuration is general enough that it could be used with isolinux or extlinux without issue).
pxe-boot is a pxe boot environment with recovery tools and a redhat kickstart environment.
Ram Disk STUFF Utility
a small utility to stuff a file into an initrd.img file inside a bootnet.img image
RamFloppy is a small ram Linux system for the purpose of system booting or repairing, a boot/rescue system.
rinse is a simple tool which allows you to bootstrap a basic installation of a number of RPM-based distributions on a Debian GNU/Linux host.
ROCK-Plug aims to replace the original hotplug package and the current hardware detection technology of ROCK Linux, called hwscan. It is designed with the KISS priciple in mind, fitting in the existing ROCK Linux framework. It features both scanning cold-plugged devices (present during bootup) and real hotplug events generated for devices plugged into a running system.
a small program designed to safely run dangerous or unreliable services
RuckusRD is a drop-in replacement for mkinitrd that is intended for use on embedded systems or removable media (e.g. live CDs), but is also perfectly usable on normal desktop Linux systems.
s6 is a small suite of programs for UNIX, designed to allow process supervision (a.k.a service supervision), in the line of daemontools and runit.
adds synchronisation and integrity-checking to the operating system "service startup" phase, allowing a computer's services to start in parallel. Without parallelism, "service startup" is typically the most time-consuming part of the boot process
Smart Boot Manager
Smart Boot Manager is an operating system independent Boot Manager - a program that is loaded by the bios before any operating system and allows you to choose the operating system to boot.
Shag/Os LOader is a command or menu driven (through shell scripts) boot loader for ShagOS, Linux, Plan9, Brazil, Inferno, and other PC OS's. Provides ramdisk support, unzip (for compressed kernels, ramdisk images, etc), simple kernel debugging, console I/O, a file system, and BIOS call ability, and much more for protected-mode 32-bit kernels and other standalone programs.
Splashy is a complete user-mode, POSIX, boot splashing system that uses framebuffers to paint a progress bar and images to the screen.
Super Grub Disk
Super Grub Disk is a bootable cdrom, floppy or usb oriented towards system rescue, and more specifically to boot and restore of boot.
Syslinux is a collection of boot loaders for Linux and other operating systems which operates on Linux ext2/ext3 filesystems, MS-DOS FAT filesystems, network servers using PXE firmware, or from CD-ROMs.
System Rescue CD
a linux system on a bootable cdrom for repairing your system and your data after a crash. It also aims to provide an easy way to carry out admin tasks on your computer, such as creating and editing the partitions of the hard disk
Ultimate Boot CD
Ultimate Boot CD allows users to run floppy-based diagnostic tools from CDROM drives.
UNetbootin allows for the installation of various Linux/BSD distributions to a partition or USB drive, so it's no different from a standard install, only it doesn't need a CD. It can create a dual-boot install, or replace the existing OS entirely. Read more
UserRC is a small program to run from rcNG to start or stop user processes at bootup and shutdown. A few security checks are performed, and the user's rcNG scripts are run as the UID of the owner.
a graphical configuration interface for the LOADLIN bootloader. It also has multi-language support including English, French, German, Italian and Spanish
Extended Operating System Loader is a free full-featured boot manager with a real, easy-to-use and full-blown graphical user interface.