Finnix is a free, self-contained, bootable Linux CD distribution ("LiveCD") for system administrators, based on Debian. You can mount and manipulate hard drives and partitions, monitor networks, rebuild boot records, install other operating systems, and much more. Finnix includes the latest technologies for system administrators, hundreds of sysadmin-geared packages, and much more. And above all, Finnix is small enough to quickly download and write to a USB thumb drive or burn to a CD. Finnix is not intended for the average desktop user, and does not include any desktops or productivity tools in order to keep distribution size low.
Visit the developers website here:
https://www.finnix.org/
Donate to the project here (and get stickers if you donate $10 or more):
https://www.finnix.org/Free_stickers