Well, Flying, Psychic, and Water have been paired with every single type, so that means they have been paired with the most, with 17 pairings. As for the least, Normal has been paired with the least amount of types. Sense it doesn’t have a pair with Ice, Steel, Poison, Rock, Bug, or Ghost. This takes 6 away from the 17 possible pairings, leaving it with only 11 pairings.
Hope I helped!