I recently purchased the Zone System from Blake Rudis at F64 Academy. Check out his You Tube Channel . It is a Photoshop Plug-in, but more than that, for post processing and follows the following theme. First you deal with Tone, then move to Colour and then Artistic Effects. Apart from what it can do, which is a lot to enhance an image, it also almost deliberately slows you down, which is a good thing.
Blake talks a lot about photographers being artists, and with the Zone System, you certainly get to feel it. You have a palette to work with, and it kind of feels at times you are dabbing paint on to your image.
Anyway, here is my first outing with the plug in. This is a photo taken some time ago of the Mezquita Cathedral Mosque in Cordoba. It was at the top in one of my folders in Lightroom. I'd never given it much thought. But anyway. Here you can see what the RAW photo looked like and then after with the use of the Zone System in Photoshop.