Favourite shipgirls would probably be Tirpitz, Belfast, Enterprise and Rodney. Belfast was my first ship to reach level 100 despite getting Enterprise and other ships such as Z23 and Eugen since when I basically started, and Tirpitz was probably the ship I have wanted the most, and having more torpedoes is always fun. Enterprise is just a completely solid ship and has helped with basically everything, and Rodney has helped since near the beginning, though may be replaced on my main fleet by Tirpitz so I can place her in another fleet, such as an HMS fleet. Shoukaku and Zuikaku are up there because I like Risa Taneda's voice acting for them, even if I do keep here Rize from GochUsa.
Current Main Fleet, Z23 will probably be replaced by Javelin or Ayanami one I get them to 100 and retrofited, and as previously mentioned Rodney may be swapped with Tirpitz at some point.