Yes, there are a lot of hidden ones. In v0.1.1 there should be 59 total. I thought I put on the signs in the art gallery how many of each set there were, but apparently I only put them on Vicky. That will be fixed in the next update.
I think that there are some doubles, as my inventory shows that I have 2 copies of at least 2.
I can't remember which two it is, but I know that one of them was a Jessie.
Also, one of the Jessies will say "Received Jessie Reverse 04" when you find it.
