Not all PRR big steam has been done. There were a few "non standard" PRR big steam that has yet to be done...
Like the PRR 2-8-8-0 HC1
USRA 2-10-2 N2 class
PRR modified 2-10-2 N2sa
PRR 2-6-2
You also have the PRR K3 class that 5 were sold to the N&W!
Plus another round of PRR T1's!