*In generation 1, there were only 3 dragon types all in the same family and the same went for ghost-types. Coincedentally, they are the only 2 types that are super effective against themselves.
*Generation 3 is the only generation so far with pure steel-types (Not counting Arceus with the steel plate because it's not usually a steel-type).
*Even though dragons breathe fire, there is yet to be a combination of fire and dragon Pokemon.
*There is yet to be a pure Flying-type (Aside from Arceus because it's not normally a flying-type).
*Flying types have been a combination with every other type except for fighting.
*Bibarel is the only non-pure Normal-type that's still weak against fighting-types.
*There are more water-types than any other Pokemon.
*Each pachyderm Pokemon is a ground-type except for Drowzee and Hypno.
*If a Ditto was fighting another Ditto and they couldn't switch out and are still in Ditto form, the battle would never end because they'd keep transforming into each other.
*In one of the Pokemon Episodes (Specifically Haunter vs. Kadabra), Ash said ghost-types are strong against Psychic Pokemon, however, this wasn't true until generation 2 and at the time Ash said taht ghost-types are strong against Psychic types, they had no effect on psychic-types.
*Even though Magnemite and Magneton are steel-types, they couldn't learn any steel attacks until generation 4.
*Agatha is supposed to be a ghost-type Pokemon elite 4, even though she mostly uses poison-types.
*Some episode guides said that Princess versus Princess was the first Orange Island episode, even though Ash wasn't on the Orange Islands at that time.
*In the anime, Snubbull, Marril, Ho-Oh, Togepi, Donphan, Ledyba, Bellossom, Elekid, Hoothoot, Slowking and Lugia are all Johto Pokemon that appeared before the Johto season (Post any of the Johto Pokemon I missed that appeared in the anime before the Johto journeys).
*There are no Pokemon songs in SSBB that played the exact same way they did in the Pokemon games they were first heard.
*Each Pokemon that ends in the letters 'don' is a ground-type except for Shieldon and Bastiodon.
*If there were a GBA version of Pokemon Yellow (Like the one in Firered&Leafgreen) the player would be able to get Raichu unlike Yellow players because they'd be able to go to Four Island and leave Pikachu at the day care with a Ditto and it would have an egg containing PIchu that they'd be able to evolve into a Pikachu and then into a Raichu.
*There is yet to be a dark-type Pokemon gym.