Python attributes without boilerplate

https://github.com/hynek/characteristic

Universal encoding detector for Python

https://github.com/chardet/chardet/

HTML template engine for Python

https://cheetahtemplate.org/

Highly-optimized, pure-python HTTP server

https://github.com/cherrypy/cheroot

Python framework for command line utilities

https://liw.fi/cliapp/

Python package for creating command line interfaces

https://github.com/mitsuhiko/click

Black box testing of Unix programs

https://liw.fi/cmdtest/

Cross-platform API to print colored terminal text from Python apps

https://github.com/tartley/colorama

Command line argument to object parsing library

https://github.com/chrissimpkins/commandlines

CFF subroutinizer for fontTools

https://github.com/googlei18n/compreffor

Drop-in replacement for argparse

https://pypi.org/project/ConfigArgParse/

Simple but powerful config file reader and writer

https://github.com/DiffSK/configobj/

INI style configuration file parser

https://pypi.org/project/configparser/

Provides symbolic constant support to Python projects

https://pypi.org/project/constantly/

Backports and enhancements for the contextlib module

https://pypi.org/project/contextlib2/

Python API for ISO country, subdivision, language and currency

https://pypi.org/project/pycountry/

Code coverage measurement for Python

https://coverage.readthedocs.io/

Cryptographic recipes and primitives for Python developers

https://github.com/pyca/cryptography

Test vectors for the cryptography package

https://github.com/pyca/cryptography/tree/main/vectors

Cssselect parses CSS3 Selectors and translates them to XPath 1.0

https://github.com/scrapy/cssselect

CSS selectors for Python ElementTree

https://github.com/Kozea/cssselect2

CSS Cascading Style Sheets library for Python

https://github.com/jaraco/cssutils

Cubic-to-quadratic bezier curve conversion

https://github.com/googlei18n/cu2qu

Coroutine-based library for concurrent Python systems programming

https://github.com/dabeaz/curio

Composable style cycles

https://github.com/matplotlib/cycler/

Well-behaved daemon framework for Python

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

Datadog Python library

https://github.com/DataDog/datadogpy

Extensions to the standard Python datetime module

https://dateutil.readthedocs.io

Python bindings for the D-BUS messaging system

https://dbus.freedesktop.org/doc/dbus-python/

Data-Driven Tests for Python Unittest

https://readthedocs.org/projects/ddt/

Better living through Python with decorators

https://github.com/micheles/decorator

Set of flexible objects for representing UFO data

https://github.com/typesupply/defcon

XML bomb protection for Python stdlib modules

https://bitbucket.org/tiran/defusedxml

Linux OS platform information API

https://github.com/nir0s/distro

Python library for DKIM email signing and verification

https://launchpad.net/dkimpy

Manipulate DNS records on various DNS providers in a standardized way

https://github.com/AnalogJ/lexicon

DNS toolkit for Python

http://www.dnspython.org/

Python library for the Docker Engine API

https://github.com/docker/docker-py

Python bindings for the docker credentials store API

https://github.com/shin-/dockerpy-creds/

Pythonic argument parser, that will make you smile

http://docopt.org/

Python Documentation Utilities

https://docutils.sourceforge.io/

Helpful CLI utilities for querying and connecting to EC2 instances

https://github.com/FlipPath/ec2-cli-tools

ECDSA cryptographic signature library (pure python)

https://github.com/warner/python-ecdsa

Robust email address syntax and deliverability validation library

https://github.com/JoshData/python-email-validator

Extensions to py-rich

https://pypi.org/project/enrich/

Discover and load entry points from installed packages

https://github.com/takluyver/entrypoints

Python 3.4 Enum backported to 3.3, 3.2, 3.1, 2.7

https://pypi.org/project/enum34/

Bindings to the Linux input handling subsystem

https://pypi.org/project/evdev/

Distributed Python deployment and communication

http://codespeak.net/execnet/

Useful extra bits for Python

https://pypi.org/project/extras/