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
Ghost types are quite neat. I have found that the majority of my favourites turn out to be rock, ground, and steel types. I like big rocky and metal things!
My personal favourite ghost-type line has to be Litwick -> Chandelure.
Absolutely, if I were a Pokemon character lampent would be my picachu.