I’ll go with swoobat, as it was part of my team through my first pokemon game. As much as I love all of those, I would have liked noivern more if it’s shiny stayed teal and black (like noibat), however, when you evolve it, it becomes a more green ish teal, which I personally don’t like very much.
Gliscor was also part of my first game, but I just love swoobat-
Crobat, ah, I have good memories with it. I got a random Japanese Zubat through wonder trading in Moon, since it wasn’t nicknamed, as soon as it became a golbat, it’s name became in English, it was my highest leveled pokemon on my team, first to reach level 99, and was very good, Crobat helped me a lot throughout my play through