Tool for recovering partitions after partiotion table loss. Extended partitions may not be detected correctly.
[testdisk](http://www.cgsecurity.org/wiki/TestDisk) is similar to
gpart but also recognises Linux RAID and LVM 2.
Very handy tools for copying from damaged media or combining more damaged sources.
partimage (homepage) is a tool for backing up and restoring whole partitions (without unused space and may be compressed). It has also server for restoring over network.
Powrfull backup system (homepage).