TaggTool - The Personal File Tagging Utility.
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.
Elyse - The free version allows up to 30 tags.
TMSU - TMSU is a tool for tagging your files.
TagFlow - TagFlow is an intelligent files manager that use tags for organize your documents.
TaggedFrog - Based on the convenient drag ’n’ drop technique, TaggedFrog allows you to organize your files...