It's why I've resisted doing a lot of categorizing. I have Favorites and Cardfarming and such. There is Depressurizer, which might help you restore your cats quickly; never used it tho.
http://lifehacker.com/depressurizer-tidies-up-your-steam-library-478976640
http://lifehacker.com/depressurizer-tidies-up-your-steam-library-478976640