The shader toggle functionality currently toggles between shader passes which can be problematic since some of shader configurations utilize more than one pass. It would make more sense to have the ability to toggle between a user predefined select of saved shader presets instead. It shouldn’t toggle through every single shader available, but instead let the user define which shaders.
I use the shader next/previous keys to switch between a few cg and cgp files in the root of my shaders folder just fine. I just picked out the ones I like from common-shaders. I had to do some editing of the cgps to make sure they pointed to the correct directories containing their cgs and other files, since I’m not using a full set from common-shaders. Royale took even more work since I had to go into it’s src folder and edit many of the include directories to make the shader portable. I uploaded a zip of my shaders folder here: https://www.dropbox.com/s/er35v1n2j8m84wq/Shaders.zip?dl=0