Contact Merger helps you to fight duplicated contacts. It performs a deep analysis of your contacts and provides you with a simple list where you can quickly merge duplicates or flag false positives. You can undo every merge/flagging in the Action Log screen, making Contact Merger 100% safe to use.
All your contacts will be rescanned on a regular basis, meaning you'll never have to worry about duplicated contacts again.
Contact Merger works offline and ad free. It was written / published because I needed a tool to merge more than 500 duplicates.
The source code is available at https://github.com/rtreffer/ContactMerger
Issues can be reported at https://github.com/rtreffer/ContactMerger/issues