Super Grub Disk is a bootable floppy or CDROM that is oriented towards system rescue, specifically for repairing the booting process. Super Grub Disk is simply a Grub Disk with a lot of useful menus. It can activate partitions, boot partitions, boot MBRs, boot your former OS (Linux or another one) by loading menu.lst from your hard disk, automatically restore Grub on your MBR, swap hard disks in the BIOS, and boot from any available disk device. It has multi-language support, and allows you to change the keyboard layout of your shell.
Rescatux is a GNU/Linux rescue CD that comes with Rescapp, a nice wizard that will guide you through your rescue tasks. It can restore Grub to the MBR update a Grub configuration, perform filesystem checks, fix a Windows MBR, and more. Features that can indirectly assist the rescue process include chat programs to let you reach human online help, a share log (automatic pastebin), and a share log that uses formatting appropriate for posting on a forum.
Super Grub2 Disk is a bootable floppy, CDROM, or USB system which lets you boot into your system. It is simply a Grub2 disk with a lot of useful menus. It can try to autodetect all of your operating systems, load your grub.cfg configuration file, and load grub2's core.img, even if the mbr is damaged. It has multi-language support.