DiskWarrior - DiskWarrior, the world's most advanced and highest rated hard disk, hard drive, and disk repair and data recovery tool for macOS, OS X and Mac OS X.
Acronis Cyber Protect Home Office - (Formerly Acronis True Image) Complete protection for your digital life
Data Rescue - When Apple's system recovery fails, recover any and all files with Data Rescue 3. This data rescue software will even work if your Mac's hard drive fails to mount.
Easeus Disk Copy - EaseUS is a suite of data recovery and protection software designed to bring back files that have been lost, destroyed or accidentally deleted and protect existing files from suffering the same fate.
MiniTool Power Data Recovery - MiniTool Power Data Recovery is a freemium data recovery tool that works quite well considering the basic version is the only free aspect of the app.
HDclone - HDClone by Miray Software is the universal tool for cloning disks and other mass storage media fast and easily. To be used for backups, data recovery, system migration and professional duplication of several disks at a time.