Components of the concept of Developmental Noise?
There are two good papers on this that I like a lot: 

Noise in Gene Expression: Origins, Consequences, and Control

Cellular decision making and biological noise: from microbes to mammals.

I think they can tell you better than I can, but the major other source of noise is extrinsic noise. Extrinsic noise typically is taken to means two things (both of which are related): 
1. Physical noise from the environment that affects biological processes (thermodynamic fluctuations, for example)
2. Intercellular heterogeneity caused by, for example, unequal division. This is also related to cells not being "well mixed" - essentially, molecules found inside of cells are not evenly distributed throughout it. 

There may be other kinds of noise, but I think extrinsic is really the main one you should think about.