I've been looking around the site, and have found a few girls that I like, but I don't know who they are.

Firstly, there's this girl from the main site's banner: https://static.istripper.com/img/landing/istripper-girl-1.jpg

Then this girl from a screenshot of a scene someone's made: http://www.virtuagirl.eu/customdata/forum/2016-07-01/V1q78bE5.jpg

And then 3 girls from a screenshot of a scene someone's made: http://www.virtuagirl.eu/customdata/forum/2015-10-21/29408_3939899_351882042648109900_HDE-Home-Entertainment---Bedroom.JPG

I'm looking for the girl in the middle with pigtails, the girl in the middle with curly hair, and the blonde girl wearing a hat. Thanks

http://www.virtuagirl.eu/customdata/forum/2016-07-01/V1q78bE5.jpg
this girl is Lucy LI
http://www.virtuagirl.eu/customdata/forum/2015-10-21/29408_3939899_351882042648109900_HDE-Home-Entertainment---Bedroom.JPG
the blonde girl wearing a hat. maybe shi is NIkky case?

In the first link, the banner one is "Isizzu" and the second one is Lucy Li just like @ILoveMandy said.

In the group screenshot the 3 girls you are asking for is the following from middle to the left.. Isizzu, Heidi Romanova & Nikky Case.

The curly haired girl is Heidi Romonava, the hat girl is indeed Nikky Case...

The girl on the bed is Anissa Kate, the girl in the picture at the wall is Antonia and the half covered girl in the background is Anna Polina.