So, ndg-httpsclient, mrjob, numpy, scrapy, monotonic and possibly others do have python3 compatibility.
Then there's a bunch of deployment tools like ansible, fabric, and marionette which don't really need to be python3 compatible for use.
Then there's tools like MySQL-python, python-gflags, python-cjson, INITools, filechunkio, which have python3 compatible alternatives, often in the standard library.
That brings the total up to 331
That leaves basically 3 categories of things left: mozilla tools, database connectors (many of which probably have python3 bindings though I haven't looked), and single sign on tools. Those account for 12 of the remaining 29 libraries.
That's pretty ready.