Typically, characters like Sakura could be one of the main female characters. She is strong - willed and her presence in a hypno - harem situation could add a lot of drama. Another could be Hinata, with her shy yet determined personality. Her relationship with Naruto in the context of a harem would be interesting to explore.
There could also be some original female characters created specifically for the 'naruto hypno harem fanfic'. These characters might have unique powers that are related to hypno or are influenced by it. They could be from other hidden villages and come to Konoha due to the allure of the hypno - based situation that Naruto or another male lead has created, and then become part of the harem.
Well, in some 'naruto hypno harem fanfic', Tenten might also be a main female character. She is a skilled weapon user, and her no - nonsense attitude would be a great contrast to some of the other more emotional female characters in the harem. Also, Ino with her mind - related abilities could be a key figure, especially considering how hypno is related to mental manipulation in this kind of fanfic.