I just remembered what #1 is, but I'll hold off since I think we're supposed to limit our guesses to 2 per set in order to give others a chance. Or maybe I'm misremembering this rule? This set is making me all nostalgic for the Psychotronic Encyclopedia of Film, since I'm remembering some of these films and images from that fine book. I'm pretty sure the images for The Beach Girls and the Monster and They're Coming to Get You were both in the book, as well as a different photo from #1.
Here is a new set. The last picture may be difficult as it shows the common artwork for Make Them Die Slowly but is for a different film.