Ported LibNoise  noise library from LibNoise.Xna to Unity. Like those two, it is released under the LGPL. Generates Perlin, RiggedMultifractal,Voronoi and Billow noises and has Operators for combining them. Noise2D is a convenience class for creating Texture2D from noises.
Available from the Showcase forum http://forum.unity3d.com/threads/68764-LibNoise-Ported-to-Unity?p=439185#post439185