The Silence of the Lambs is more of a crime movie, than a horror movie. Fact!

Sure it has a few horror elements (mostly psychological, and perhaps the finale), but Buffalo Bill doesn't actually stalk and kill people during the movie and it's more about the investigation and discovering the whereabouts of the serial killer than outright horror. Never understood people that think otherwise really..

And Se7en has more murders but the fact they are not shown in any graphic detail stops it from being an outright horror again. The only scene I would consider close to being horror-esque is that famous jump scare.. I guess it inspired Saw in some ways, but the difference between Se7en and Saw is Saw is more focused on the actual horror and scares, and less on the police investigation.