Not particularly like that, I mean that if I click an item (like a Romance tag) inside a user category named Fanfiction, I want to have it so it filters by Romance and Fanfiction tags. And if I click on a different item (Suspense tag, etc) inside the Fanfiction category, it will filter by Suspense and Fanfiction tags. I think it would be more visually appealing instead of having a list of saved searches for each genre.
]Fanfiction (Tag 'Fanfiction' added to all child items)
-]Genre
--]Romance tag (If clicking this, add Romance tag to Fanfiction tag in search)
--]Suspense tag (tags:"=Suspense" and tags:"=Fanfiction")
If it isn't currently possible, but might be able to be in the future, then I think it would be a neat idea to have

. For now I will work with what you mentioned with the hierarchical searches. Thank-you for your time in responding to my question.