Yeah, danbooru or similar image boards basically have all the things talked in this tweet thread.

They have tag aliases, meta-tags and so-called "tag implications".

The last one is basically sub-tags but with more flexibility and dead simple to implement: if A implicates B, then tagging an image with A will automatically tag it with B. So you can tag "American Male Novelist", and then the system will automatically add "American", "Male", "Novelist", "Writer", etc. (after such implications were added).

It much easier than Wikipedia's categories, but Wikipedia's way is of course intentional because categories is meant to have a stronger hierarchy than mere tags.