This was linked to on DPReview and PetaPixel a few days ago. It's an interactive web page that shows you context sensitive Photoshop and Lightroom keyboard shortcuts. When I say interactive, I mean it responds in real time to whatever modifier key, or combinations of modifier keys, is/are being pressed. I am not altogether sure how useful it is, because of my occasionally moaned about shite internet connection, (real time has at least a ten second delay for me). Anyway, check it out, and park it on one of the multiple monitors you have connected to your desktop system.
So far it works for Photoshop, Lightroom and Blender, and for Windows and Mac
http://waldobronchart.github.io/ShortcutMapper/#AdobePhotoshop
I've actually found a couple of useful short cuts via the app, that I might actually use in the future.
This is how it looks with Shift Ctrl held down