My best pal and I often buy each other complete stinkers (you know the kind - costs a pound in some awful second hand shop), it's an ongoing mission to seek out the worst film in existence, outside of the predictable ones. So sadly I have quite a few hellishly awful films. Here's a few -
Queen Kong.
Abducted By The Daleks.
The Wild World Of Batwoman.
Blackula.
The worst "unreleased" films I own are without doubt Fantastic Four (1994 version) and Star Wars Holiday Special. The Star Wars one is arguably the worst thing I've ever seen, Chewbacca even has a family, and his son is called Lumpy. Yes it's THAT bad.