I've heard a lot of people talk about how certain Pokemon (e.g. Unown) are only good to use if they have "Psychic-type HP", and I haven't been able to find out what that means. Can anyone help out?
HP stands for Hidden Power. It's a move that has a different type depending on specific characteristics of a Pokemon. Therefore, people say that Unown needs to have Psychic Hidden Power to be even slightly good, because it's the only move it would get STAB on.
Hope I helped!