Well done for coming up with some great topics Dem.
As to suggestions, how about Mad doctors/scientists.
Have we done Monster Movies as in King Kong/Godzilla/Gwangi/Sinbad etc.
Evil Kids - Omen/the bad seed/children of the corn etc.
Freak or unique - Elephant man/Freaks/mutations etc.
Dream based or surreal - Freddy films/dreamscape/dream demon/David Lynch
Art films - El Topo/Weekend/Hourglass Sanitarium
Animations - Disney/Ralph Bakshi/Jan Svankmayer/Fantastic Planet etc..
Comic/graphic novel based - Superheroes/Watchmen/Hellboy/Dredd/ Danger Diabolik
Favourite Special(?) day films - Halloween/My bloody Valentine/Friday 13th/Black Christmas/Bloody birthday
Top ten Villains - Darth Vader/Blofield/Freddy Kruger
Top ten most hated films.