Now that I’ve covered the big four pokemon varieties and their functions in combat, I have to aver- there are other types, but they aren’t nearly as common, and most of them are virtually one of the four main varieties, only more specialized, or with some overlap into another type. This course isn’t as vital as some of the other ones, so if you’re not terribly interested you can skip it- but remember that the information is always here on tap for you.
There exist a number of pokemon who stand at a midpoint between two varieties- often, these pokemon suffer from too many weaknesses to be used frequently. However, a lot of them serve very well as surprise variants of one of their functions, and if the rest of your team can take out threats to their greatest weaknesses, they can then act as one or both of those varieties of pokemon without fear.
An excellent example of a hybrid pokemon is Crustle. Possessed of a stunningly high Attack stat and an even higher Defense, as well as a typing that leaves it with only one weakness (Water), Crustle stands between the Tank and Sweeper functions- but cannot actually perform either on its own. Its Special Defense is only adequate, and its speed is abysmal. Provided you can take out the main Special Attack users on the opposing team, you can then break out Crustle and either tank or sweep (or both) decently. However, just to make things easier on you, Crustle also has access to the powerful boosting move Shell Smash, which cuts its Defense and Special defense by one stage in order to increase not only both its Attack stats but also its Speed by two stages. Provided it survives through two uses of Shell Smash, Crustle abruptly becomes a positively terrifying sweeper- but without some targeted takedowns or a way to prevent your opponent from acting for long enough to use the boost move, Crustle will find itself destroyed while it’s still charging up. Alternatively, Rock Polish can be used to patch up Crustle’s speed without cutting into its defenses- but again, this depends on your ability to either buy yourself time, or take out things that threaten Crustle first. Because of this, if you’re going to try to sweep with Crustle, you need a team that will properly offset its weaknesses.
Most hybrid-variety pokemon will require a team that backs them up- fortunately, a lot of their requirements are met by groups of pokemon you would want to stick together anyways. A hybrid-variety pokemon can usually be distinguished by having one or two of the defining stats of each of its varieties, but lacking one of the traits required for each variety. In Crustle’s case, its massive Attack is characteristic of a Sweeper, and its high Defense and good HP are common among Walls- but unlike a Sweeper, it has poor speed, and unlike a true Wall its moveset is lacking in defensive options to reinforce it, including nothing noteworthy in the way of recovery or ways to patch up its Special Defense.
Hybrids aren’t as popular as pure-variety pokemon, because most players will be looking specifically for the effects of a given variety of pokemon- but if you have a slot in a team where the hybrid’s weaknesses will be accounted for already, or if you are willing to adjust your team and strategy to deal with the low points of the hybrid, they can still prove an invaluable resource and a highly effective pokemon.