Magic Rescue scans a block device for file types it knows how to recover and calls an external program to extract them. It looks at "magic bytes" in file contents, so it can be used both as an undelete utility and for recovering a corrupted drive or partition. As long as the file data is there, it will find it.
Magic Rescue works on any file system, but on very fragmented file systems it can only recover the first chunk of each file. Practical experience (this program was not written for fun) shows, however, that chunks of 30-50MB are not uncommon.