>>34468509I don't know if you'll see my post at this rate, but I did some basic calculations on useful types for covering the gyms and Elite Four, and your teams most common weaknesses (Grass, Ground, and Water), although I removed Croagunk since it's post-game, so I figured you would probably change your mind on using it.
An Ice-type would be a good addition to help cover weaknesses and a few bosses, namely Drayden/Iris and Ghetsis, but they're both late game, where they would likely be less useful as a whole. If that still interests you, Cryogonal might be nice as a speedy special attacker to counter your physical-centric team.
Sigilyph has some nice typing; it can counter Fighting, Grass, and Bug nicely, and it has five weaknesses, but Dark seems like the only common one you'd encounter. Plus, Wonder Skin makes status moves miss often, which is really cool.
If you want a tank, either Ferrothorn or Cofagrigus would work fantastically. Ferrothorn has more weaknesses, and those weaknesses are more common throughout the game, but it also has many more resistances. Cofagrigus is one I've personally used, and was easily my MVP tied with Chandelure. It's ability Mummy can be occasionally useful, and has two rare weaknesses.
