There's a few starters I absolutely loved, such as Cyndaquil and Rowlet. My Decidueye has been with me throughout both the normal Pokemon Moon game and Pokemon Ultra Sun. I couldn't start over with a new Rowlet, and so I transferred him over and used him alongside my Primarina.
The one starter that has a special place in my heart, however, is Totodile. I really love that lil guy. <3