I have been working on this one for a while for my own needs, but managed to turn it into usable package for low-poly modelling.
LowPoly Factory is a procedural content generator specialized in lowpoly landscapes. The idea is to easily generate the scene and then tweak parameters/materials and do manual work to make end result original. Each object is unique, but still based on parameters you specify. There is an option to bake materials to vertex colors, which makes it easy to import models to your 3D game engine of choice.
Let me know if you get to play with it.