Ground or Rock types are also really good against Fire Users, so, maybe pokemon like Landorus-T or Landorus-I can set up pivots for you there, or it can just use Earthquake to beat those Fire types. Gyarados is also pretty good dealing with Fire types, but you can also think about other stuff like.. Psychic types who lure in dark pokemon, Mega Scizor can come in, and hit them with a bug move for your Psychich types to breathe easier too~!