So expat doesn't count as that literally wraps the expat library. Random also requires accessing the system randomization libraries to work properly so I don't think that is a candidate either. As for the compression libraries, those could be re-implemented, but I view those as wrappers around the libraries (same as the crypto stuff). I mean it doesn't have to be that way, but I'm trying to keep this framed in a tractable problem to start.

So to summarize the non-contentious modules (including adding functools) in alphabetical order, that puts us at:

array
audioop
binascii
cjkcodecs
csv
functools
itertools
re
struct

I would be curious to see what frequency these modules are used to know what might be higher priority so that the least used modules could eventually be marked as CPython-specific.

And to answer Chris' question, there is no need to be able to generate this from the docs until there is some PEP listing what modules must be implemented by a VM in order to considers its stdlib complete.

And thanks for the help so far, everyone!