Potential Amittyville "Spin-offs". (I apologize if some of them actually exist.)
Amityville Chainsaw Massacre
Amityville Rental Car
Door to Door Amityville Salesman
Amityville goes Hawaiian
Amityville Dracula
A Honeymoon in Amityville
The Amityville Bikini Blow-out!
Amityville vs The House on Haunted Hill
Amityville meets a Brooklyn Gorilla!
I saw a poster for "Amityville Barbi" yesterday so it wouldn't surprise me if they all existed.