For Full module descriptions go here – http://nonlinearcircuits.blogspot.co.uk/2013/11/pcbs-for-sale-updated-9-nov-2013.html
Non Linear circuits are responsible for some of the most original and truly forward thinking analog designs for modular synths in the past few years. Andrew the designer describes it thus:
Because we are making so many designs available for sale in one go we are not able to immediately describe each project in detail here on Thonk, so for now please consider the research into what each module does as part of the DO IT YOURSELF with some little help from these links below 
For all BOM’s, schematics and build information go here – http://www.sdiy.org/pinky/data/data.html
There are many build threads for help and information on Muffwiggler, these are good place to start