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
Crobat, my beloved. Where hast my 6 foot, 4 winged bat gone? What forces of evil have possessed GameFreak to keep me from you? Can they not see the bonds of friendship that keep me coming back to you? Dost they not know thou art perfect? Your soft purple fur, your unique typing, your winning personality? Fear not, my love. For I know that one day, you and I will be reunited! I will once again fly on your back to the Pokémon league, whereupon I will thrash the Elite Four with your STAB Cross Poison! Till then, my lavender cutie, rest your mighty wings, sweet cherub. Our time will come again.