Great classification of ringtones there.
Some topics :-
* Top Movie Songs Ringtones
* Top Natural Sounds
* Top Genre Ringtones (this category can be further ramified into different genres like Top Hip-Hop Ringtones, Top Metal Ringtones etc.)
* Top Football Ringtones
* Top Different Language Ringtones
That is all that I can think of right now. Hope this was helpful