Kitchen contains a cornucopia of useful code

https://pypi.org/project/kitchen/

Fast implementation of the Cassowary constraint solver

https://github.com/nucleic/kiwi

Fast and thorough lazy object proxy

https://github.com/ionelmc/python-lazy-object-proxy

Library for programs conforming to DNS RFCs and drafts

https://www.nlnetlabs.nl/projects/ldns/

Python support for libpeas

https://wiki.gnome.org/Projects/Libpeas

Python bindings for Libvirt virtualization API

https://libvirt.org/python.html

Python interface for XML parser library for GNOME

http://xmlsoft.org/

New features in linecache backported to Python 2

https://pypi.org/project/linecache2/

Python bindings for low-level FUSE API

https://github.com/python-llfuse/python-llfuse

Platform-independent file locking module

https://github.com/smontanaro/pylockfile

Toolkit for logging of library method calls

https://github.com/reef-technologies/logfury

Pythonic binding for the libxml2 and libxslt libraries

https://lxml.de/ https://github.com/lxml/lxml

Python binding for the LZ4 compression library

https://github.com/python-lz4/python-lz4

Python binding for the LZMA compression library

http://www.joachim-bauch.de/projects/python/pylzma

Convert markdown formatted file with reST markup to reST format

https://github.com/miyakogi/m2r

Python module for determining file type

https://www.darwinsys.com/file/

Wrapper for email standard library

https://github.com/SpamScope/mail-parser

Super-fast templating language in Python

http://www.makotemplates.org/

Implements an RFC-5804 Manage Sieve client

https://bitbucket.org/ericvsmith/managesieve3

Python implementation of Markdown

https://python-markdown.github.io/ https://github.com/Python-Markdown/markdown

Fast and complete Python implementation of Markdown

http://code.google.com/p/python-markdown2/

Implements XML/HTML/XHTML Markup safe string for Python

https://github.com/pallets/markupsafe

Ned's script to check McCabe complexity

https://pypi.org/project/mccabe/

Python interface to Sendmail milter API

https://pythonhosted.org/milter/

Fastest markdown parser in pure Python

https://github.com/lepture/mistune

Rolling backport of unittest.mock for all Pythons

https://mock.readthedocs.org/en/latest/

Python 3 monotonic time module for Python 2

https://github.com/atdt/monotonic

More routines for operating on iterables, beyond itertools

https://github.com/more-itertools/more-itertools

Python MPD client library

https://pypi.org/project/python-mpd/

Python Library for Arbitrary-precision Floating-point Arithmetic

https://www.mpmath.org/

MessagePack (de)serializer for Python

https://msgpack.org/ https://github.com/msgpack/msgpack-python

Multidict implementation

https://pypi.org/project/multidict/ https://github.com/aio-libs/multidict

Python-based audio metadata tag reader and writer

https://github.com/quodlibet/mutagen

Optional static typing for Python

https://www.mypy-lang.org/ https://github.com/python/mypy

Experimental type system extensions for programs

http://www.mypy-lang.org

Discovery-based unittest extension

https://nose.readthedocs.io/

Next generations of nicer testing for Python

https://nose2.readthedocs.io

Create NTLM authentication structures

https://github.com/jborean93/ntlm-auth

Python NTP library

https://pypi.org/project/ntplib/

The New Numeric Extension to Python

https://www.numpy.org/

Python library for OAuth version 1.0

https://github.com/joestump/python-oauth2

Generic, spec-compliant, thorough implementation of the OAuth request-signing logic

https://github.com/oauthlib/oauthlib

Python module to read MS OLE2 files

http://www.decalage.info/en/olefile

Python interface to the OpenSSL library

https://github.com/pyca/pyopenssl

Python wrapper for the OpenType Sanitizer

https://github.com/googlefonts/ots-python

Core utilities for Python packages

https://packaging.pypa.io/en/stable/ https://github.com/pypa/packaging

Parameterized testing with any Python test framework

https://github.com/wolever/parameterized

Python SSH2 protocol library

https://www.paramiko.org/

Python module for parsing 'human readable' date/time expressions

https://github.com/bear/parsedatetime

Comprehensive password hashing framework supporting over 30 schemes

https://bitbucket.org/ecollins/passlib