If you need ideas for girls to add, might I suggest Elastigirl, Charmcaster or even some One Piece girls, like Nami, Robin, Perona or Yamato?
Viewing post in v1.3.0 - Gwen 2: Living the Life comments
Oh! Charmcaster has been thought on the past, absolutely, still need to find a good way to add her...
As for One Piece girls, that would be more difficult, the focus is more on Western Characters than Anime ones.
Patreon had a poll recently were Hatsune Miku was one of the options to get a scene, but lost, so we'll see.