Warping
Being able to deform things is one of the basic building blocks of generative graphics. Transforms in general are useful, and warped distortions add interest in an unpredictable but structured way.
This article by Íñigo Quílez is a tutorial in how to use noise based warping with Fractal Brownian Motion. Code is included.
Like many fractal techniques, this warping smoothly interpolates as the input parameters change. This means that it can be used for animations and blending–and is easier to dial in to the exact look you want.
It also means that you can combine it with other techniques more easily–like I said, deformation is a basic generative building block. You can use it to warp other textures, animate a fire, subtly add chaos to the spawning regions of your a-life creatures, or affect the local parameters in your level generator.