The problem is, I want want that doesn't tell me any combinations. They all seem to have lists, all I want to know is how many categories of items there are. I see Red for fire items obviously, Blue for water, and other different colors. I am wondering how many color categories there are. Also, is there a color for items that can not be combined any further?

If anyone knows a good guide that give some clues but doesn't give away all the combos I would love to hear about it. Thanks!