I’ve lost partitions more than once due to failed linux installs, my own error, and data integrity issues, and over the years I’ve used many tools to recover. Almost all of them have been commercial solutions. Enter Testdisk, a free, open source, cross platform data recovery software. There are binaries and a recovery disk image there, as well as Photorec, a tool designed to help recover files from digital camera memory cards, which is another category of tool I’ve purchased in the past. Testdisk has the broadest format support I’ve seen in a tool and you can’t beat the price.