oktags

https://github.com/200ok-ch/oktags

oktags helps you organize your files by managing tags on them. It works by adding/removing at the end of the filename. Given a file 'cat.jpg', when adding the tags 'tag1' and 'tag2', the filename will become 'cat--[tag1,tag2].jpg'. The implementation is OS-agnostic, so it should work on Linux, macOS and Windows.