Structured Logging for Python

https://www.structlog.org/

Captures output while still printing it in real-time

https://github.com/pycontribs/subprocess-tee

Python bindings for version control system

http://subversion.apache.org/

Utility belt for automated testing in Python for Python

https://github.com/gabrielfalcao/sure

Python Library For Symbolic Mathematics

http://sympy.org/

Pretty-print tabular data in Python

https://bitbucket.org/astanin/python-tabulate

Traceback serialization library in Python

https://pypi.org/project/tblib/

Objects and routines pertaining to date and time

https://github.com/jaraco/tempora

Retry code until it succeeds

https://github.com/jd/tenacity

ANSII Color formatting for output in terminal

https://pypi.org/project/termcolor/

Collection of helpers and mock objects for unit tests and doc tests

https://github.com/Simplistix/testfixtures

Test utilities for Python code working with files and commands

https://github.com/jupyter/testpath

Repository of test results

https://launchpad.net/testrepository

PyUnit extension for dependency injection

https://pypi.org/project/testscenarios/

Extensions to the Python standard library unit testing framework

https://github.com/testing-cabal/testtools

Most basic port of Perl's Text::Unidecode module

https://github.com/kmike/text-unidecode

Pure Python TFTP library

https://pypi.org/project/tftpy/

Travel through time in your Python tests

https://github.com/adamchainz/time-machine

Complete yet simple CSS parser for Python

https://pypi.org/project/tinycss/

Low-level CSS parser for Python

https://github.com/Kozea/tinycss2

Python bindings to the Tk widget set

Separate the TLD from the registered domain and subdomains of a URL

https://github.com/john-kurkowski/tldextract

Python library for parsing and creating TOML

https://github.com/uiri/toml

Lil' TOML parser

https://github.com/hukkin/tomli

Lil' TOML writer

https://github.com/hukkin/tomli-w

Style-preserving TOML library

https://github.com/sdispater/tomlkit

Python Web Server from FriendFeed

https://www.tornadoweb.org/

Building newsfiles for your project

https://github.com/twisted/towncrier

Virtualenv-based automation of test activities

https://tox.readthedocs.org/

Fast, extensible progress bar for Python

https://github.com/tqdm/tqdm

New features in traceback backported to Python 2

https://pypi.org/project/traceback2/

Requests-like API built on top of twisted.web's Agent

https://github.com/twisted/treq

Library for async concurrency and I/O

https://pypi.org/project/trio/

Canonical source for classifiers on PyPI

https://github.com/pypa/trove-classifiers

Top quality TLS certs while you wait, for the discerning tester

https://github.com/python-trio/trustme

Python wrapper for ttfautohint

https://github.com/fonttools/ttfautohint-py

Python progress reporting to /dev/tty

https://liw.fi/ttystatus/

Collection of utilities for interacting with PyPI

https://github.com/pypa/twine

Collection of utilities for interacting with PyPI

https://github.com/pypa/twine

Asynchronous networking framework written in Python

https://twistedmatrix.com/

Python API and command-line toolset for Twitter

https://github.com/sixohsix/twitter

Compatibility API between asyncio/Twisted/Trollius

https://github.com/crossbario/txaio

Asynchronous Python HTTP for Humans

https://github.com/tardyp/txrequests

Fork of Python ast modules with type comment support

https://github.com/python/typed_ast

Runtime type checker for Python

https://github.com/agronholm/typeguard

Typing stubs for docutils

https://github.com/python/typeshed/tree/main/stubs/docutils

Typing stubs for psutil

https://github.com/python/typeshed/tree/main/stubs/psutil

Typing stubs for setuptools

https://github.com/python/typeshed/tree/main/stubs/setuptools

Backported and Experimental Type Hints for Python 3.5+

https://github.com/python/typing/tree/master/typing_extensions

Runtime inspection utilities for typing module

https://github.com/ilevkivskyi/typing_inspect