Looking for a software that will scan a folder (and all its sub-folders tree) and will output Folders that have a lot of files in common.
You can use Fast Duplicate File Finder to accomplish this if you are looking for duplicate files or duplicate files with different names in multiple directories or the same directory. Files that are similar or a duplicate with a different name will be grouped together with the folders the files are in.
From Widipedia, "Fast Duplicate File Finder is a Windows tool developed by MindGems Inc, available as a freeware version and a full commercial version. It is intended to scan a user's computer for duplicate files, display a list of such files and let the user delete unneeded copies with the purpose of freeing up hard drive space."