DiviFile - DiviFile: A Hub for Your Information
TagSpaces - TagSpaces is an open source platform for personal data management. With TagSpaces you can manage and organize the files on your laptop, tablet or smart phone.
tag2find - tag everything on your desktop like files, images, movies or music by simply using tags.
allTags - allTags is a free, tag based file management application.
TagsForAll - An excellent solution based on tags/keywords for streamlining the access to images, documents...
Tabbles - Tabbles use tags to organize and find files along with your colleagues.