Virtual Volumes View - VVV uses a relational database to store its data.
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.
Gentibus CD - The software will assist you to quickly find and categorize your files on your computer disks.
allTags - allTags is a free, tag based file management application.
GWhere - GWhere is a catalog manager which allows to maintain a database of yours CDs and other removables media.
Elyse - The free version allows up to 30 tags.