Summarize raster layers within overlapping polygons

Python code generated for the purpose of summarizing a defined set of discrete/categorical and/or continuous raster layers within zones that may be overlapping. Many widely used GIS tools to summarize raster layers within zones are not capable of handling overlapping zones. This code also allows for the computations to be completed over a number of separate raster layers at once and compiles the outputs into a single table for the discrete/categorical and continuous raster layers.
This code was originally developed to serve the purpose of summarizing landscape data (land cover, elevation, geology, etc.) for watersheds that are overlapping. Script can be implemented though for any process where a list of raster files need to be summarized within zones and compiled in a single spreadsheet.