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.
FileLocator - FileLocator Lite enables you to locate files on your pc.
allTags - allTags is a free, tag based file management application.
Locate32 - Locate32 is software which can be used to find files from your harddrives and other locations.
Elyse - The free version allows up to 30 tags.
Agent Ransack - Agent Ransack is a tool for finding files and information on your hard drive fast and efficiently.