As far as design goes most Psychic types are given powersets that revolve around a classic mental power, but are given all kinds of abilities through Pokemon moves. Hypno’s gimmick is developped around Hypnosis, but his learn set has very little to do with that overall, he can learn telepathic and telekinetic moves of all sorts instead. As much can be said about Mr. Mime’s barriers or Xatu’s future sight.
In-game mechanics stray from the specific powersets mentioned in the Pokedex to a greater degree than what happens with other typings. Take a quick look at Pokemon that learn Slash and often you’ll see a physical extension of their body with cutting abilities, the Psychic equivalent, Psychocut, doesn’t seem to depend on design at all. Flexibility is one of the main sale points of Psychic as a typing so limiting what a particular pokemon can do is a no go. Consider that “being able to see the future” concerns a very narrow moveset when compared with “manipulates water” or “generates heat”. This is both a curse and a blessing, often Psychic pokemon come out as less special when compared to each other from a mechanical standpoint, but from design and visuals they have a much bigger freedom!
Telekinesis is also one of the universal fixes that Game Freaks has used over the years to provide us with some creative/uncommon design choices. There is a pokemon archetype that could be defined as “a common-day object that moves on its own”, Chimecho is essentially a floatting windbell, Claydol is a primitive doll and Unown is simply a floatting gylph. These objects lack of any “inherent mobility” that would cast them as friendly characters, so instead they just “float around”. Telekinesis was just the excuse to make it happen. This was specially common in the first few generations as back then Ghost was even rarer as a type than it is now. Indeed, the commonplace practice has shifted and most “animated objects” will now be more likely “possessed by a ghost”. Funnily enough, as Darmanitan enters Zen Mode it gains a Psychic typing and loses mobility becoming just like the original dolls that inspired its design.
One last concept that I’d like to bring up is that the more animalistic Psychic types have reduced personality traits when compared with the ones that are developped in their behavior. This is interesting because it implies that inherent mental powers are also a trait of animal minds and that human-like intelligence is not necessarily linked with a higher mind power. Powerful Pokemon in the series are almost forces of nature and it’s a good touch to give mental abilities to such dehumanized figures. It should be crystal clear that in the Pokemon world intelligence goes well beyond human beings, but giving superior minds to non-human entities is a more daring endeavor. It begs the question of “why are the humans so special?” which is one of the question that the series insists in leaving unanswered (partly because it’s a bit too religious for a kid’s game 😀 ).
I’m likely to elaborate a bit on the intelligence and human-like personality of Psychic types sometime soon, as I intend to talk about Mewtwo in detail. Until then, may your telekinetic pants keep you afloat.