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.
TMSU - TMSU is a tool for tagging your files.
allTags - allTags is a free, tag based file management application.
Hydrus - A personal booru-style media tagger that can import files and tags from your hard drive and popular...
Elyse - The free version allows up to 30 tags.
File Name Tag Explorer - File Name Tag Explorer lets you: Organize your files with tags.