Just something I've been playing with this morning. feel free to use it or modify it if you wish.
I wanted to try and create terrain just using math functions and a displace node. depending on the values you change the constant scalars to you can get some interesting effects, like the start of random craters, as in image 2. You can then use them as masks for the colour shaders. kind of reminds me of some odd alien world. perhaps it could be used for clouds some way, or water.
anyway use if you want, a please let me see what you create if anything