Learning more and creating complex image effects

Hello, I recently wanted to learn about and apply image effects to my projects/games. (Obviously) I know very little about them. I really like image effects because it enhances the view of the game a whole lot since I am working on a horror game I thought spooky and scary image effects would increase the quality of my game.

I started learning about them and was able to get my hands on the basic image effects that tutorials give out (motion blur, vignette, fog, etc) but I can't find either on the asset store or online about more complex image effects. I seen them in games before like how the screen gets all distorted or choppy, I want stuff like that for my horror game and I can't seem to find that stuff anywhere and I see this type of subject is not so popular. Is there anywhere I can get some cool, more complex image effects or atleast learn how to make them, shader scripting is different then C#, or maybe I am typing in the wrong things to search on google... thank you so much