Other than Andrew Price’s quite old and dated (though still good) “The Wow Factor” ebook, are there any other good resources, in ebook, print, or video formats, that walk you through the things you can do after an image is rendered to help it to stand out? I don’t see this talked about much, or at least focused on, even on some of the sites I visit frequently.
Or is there a guide, similar to the Cycles Encyclopedia for the compositor nodes?
I have made a variety of compositor tutorials, there might be something in there that you find helpful? https://www.youtube.com/playlist?list=PLZI9BDZ5udV1N9HqS9C1wxnFhXV28bbYR
LOL Should have realized that was you! 
Are most of those aimed at the VSE? I’m looking for things that I can used to improve my “still” shots.
Sorry probably not, most of tuts are targeted at motion effects. I find that post processing depends very much on the feeling you want to evoke in the image. So its a horses for courses issue. Sparkles and glows probably don’t apply to Space ship hallways much.
I will cruise around Pintrest collecting image styles and treatments, then look at what I have to work with in Blender and develop ways to create those effects. You do need a critical eye to understand what is happening in those treatments however.