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.
Tabbles - Tabbles use tags to organize and find files along with your colleagues.
allTags - allTags is a free, tag based file management application.
TaggedFrog - Based on the convenient drag ’n’ drop technique, TaggedFrog allows you to organize your files...
TMSU - TMSU is a tool for tagging your files.
Leap - With Leap you find things based on your natural memory of that file.