I managed to get a new category added on there. Well, a subcategory. I had uploaded some Millions Knives fanart but couldn't find a subcategory for him so I had to put it simply under "Trigun". I then sugggested in the Category Requests forum that they add this and they did! The requirements for adding a new category are simple.

1. You had to have already uploaded a piece of fanart that would fall under the suggested category.

2. Find at least 15 pieces of fanart. They can be from any website. I managed to find 20 pieces of Knives fanart on Fanart-Central under "Trigun" on the first three pages alone.

Needless to say, the subcategory was added right away.