Mountain Ranges

@Zenithspeed I'm pretty sure it's all just multiple layers of Perlin noise, with different parameter values on different layers giving you a large amount of visible terrain variation. I watched a video recently that went through the more technical aspects of terrain generation for video games, and it showed how just a few layers of noise can create very realistic terrain features of almost any type or scale with just a little tweaking of input values.

Also, I think you're right about the domainwarp thing, it's probably an entire layer of noise that stretches or compresses the terrain on a larger scale

these are just very rough guesses, but the yellow outlined one you can get by fiddling with fractal domainwarps (to make them long) and a mask noise (to filter where the mountains will appear), the red outlined one could probably be achieved by some kinda billow noise thing