Most popular 'horror' edits, I could make to my movie footage/ photography..

De-saturate, Gaussian blur, add film grain to the image, blood brushes, sepia effect, inverting effects, grain extract mode, white balance (photography, changes overall colour filter.) contrast edits,

SCI FI Edits

Diffusion glow to text, titles and images
Contrast edits
Vibrance + Saturation edits
Lens vignetting
(Photography) sun flare edits