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.
TaggedFrog - Based on the convenient drag ’n’ drop technique, TaggedFrog allows you to organize your files...
TagFlow - TagFlow is an intelligent files manager that use tags for organize your documents.
Tagger - Tagger is a small application for OS X that can be used for quickly adding arbitrary textual tags...
Tabbles - Tabbles use tags to organize and find files along with your colleagues.
Leap - With Leap you find things based on your natural memory of that file.