Good rules for stress and dealing with stress in the Cyberpunk or related RPG systems. Also a few other add ons for other things that will keep your PCs guessing.
an old classic for Cyberpunk 2020 with some strange supernatural/horror meets Cyberpunk themes going on. I used this back when it was new and in print and got a lot of mileage out of it. The PDF is a pretty good scan, not bad.