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
hard to pick just one. Flareon just barely eekes it out to the top but it has the unfair advantage of being my first starter, from Gale of Darkness on GCN. my fantasy team would be
Flareon Swampert Decidyueye Gallade Drampa or Altaria Alolan Dugtrio or Clodesire