the pokemon from helllll o-o;; that would be groudon maybe. i don't think they are missing any types. =/ ground, rock, water, ice, psychic, dark, fire, grass, bug, flying, fighting, normal, metal, electric, poison...ect; x) the other elements i can think of:
mud
sand
rainbow (weak to all types, strong to all types)
air (uh...without air we die?)
wave? (includes sound waves, UV waves, ect;)
and if there are dragons, why not phoenix types =-=;; *shrugs*
mist/dew types
sun/light type