Personally, mine is joint first between Sandshrew (the cutest), Espurr (most relatable), and Gastrodon.
After those, in no particular order, I like Turtwig (best starter, fight me), the Roggenrola line (little rock guys), the Litwick line (candles and lamps with nefarious intentions), and Metagross (cool robot thing).
Kyogre is the best legendary in my opinion
I believe the reasoning for the weaknesses of Psychic type are based on different phobias (scared of the dark, bugs, and ghosts). Also, it makes bug types just that little bit stronger which is nice!