Data interchange format library

https://github.com/protocolbuffers/protobuf

Code generator and libraries to use Protocol Buffers from pure C

https://github.com/protobuf-c/protobuf-c

Core Protocol Buffers library

https://mvnrepository.com/artifact/com.google.protobuf/protobuf-java

Data interchange format library

https://github.com/google/protobuf

Converters for simple fixed-width bitmap fonts

http://www.seasip.info/Unix/PSF/

New shell made entirely out of a Perl script

https://metacpan.org/release/psh

Conversion utility to convert Psion 5(MX) files into other formats

https://frodo.looijaard.name/project/psiconv

Utilities for manipulating PostScript documents

http://gershwin.ens.fr/vdaniel/Doc-Locale/Outils-Gnu-Linux/PsUtils/

GNU Portable Threads

http://www.gnu.org/software/pth/

GNU Portable Threads

http://www.gnu.org/software/pth/

Cross platform C++ library, used by OPAL

http://www.opalvoip.org

Public Suffix List by Mozilla

https://publicsuffix.org/

Light-weight, simple and fast XML parser for C++ with XPath support

http://pugixml.org/

Script to update snort-2.8+ rules

https://github.com/shirkdog/pulledpork/

Sound server for UNIX

http://pulseaudio.org/

Discord plugin for libpurple

https://github.com/EionRobb/purple-discord

Facebook plugin for libpurple

https://github.com/dequis/purple-facebook

Free Blizzard Battle.net emulation software

http://pvpgn.berlios.de

The Video4Linux PWC webcam viewer

http://raaf.atspace.org/

Finite-state machines in Python

https://github.com/glyph/Automat

Python parser for the CommonMark Markdown spec

https://github.com/rtfd/CommonMark-py

Fast and easy to use stand-alone template engine

https://jinja.palletsprojects.com/en/3.1.x/

Piecewise linear interpolation in multiple dimensions

https://github.com/LettError/MutatorMath

OpenGL (and related library) interface for Python

http://pyopengl.sourceforge.net/

Iconic fonts in PyQt and PySide applications

https://github.com/spyder-ide/qtawesome

Abstraction layer on top of the various Qt bindings

https://github.com/spyder-ide/qtpy

Store passwords using the SecretService DBus API

https://pypi.org/project/SecretStorage/

Small text templating language

https://pythonpaste.org/tempita/

ACME protocol implementation in Python

https://github.com/certbot/certbot/tree/master/acme

Simple DNS resolver for asyncio

https://pypi.org/project/aiodns/

FTP client/server for asyncio

https://aioftp.readthedocs.io/

Async http client/server framework (asyncio)

https://github.com/aio-libs/aiohttp

Python library for accessing PostgreSQL database using asyncio

https://github.com/aio-libs/aiopg

Python asyncio (PEP 3156) Redis client library

https://github.com/aio-libs/aioredis

AsyncIO bridge to the standard sqlite3 module for Python 3.5+

https://pypi.python.org/pypi/aiosqlite

Modified Kr Sphinx theme

https://github.com/bitprophet/alabaster

Radically simple IT automation

https://www.ansible.com/

Checks playbooks for sub-optimal practices and behaviour

https://github.com/willthames/ansible-lint

Extensible embeddable ansible job runner

https://ansible-runner.readthedocs.io/

Namespace control and lazy-import mechanism

https://bitbucket.org/hpk42/apipkg

Python module for determining platform-specific dirs

https://github.com/ActiveState/appdirs

Secure Argon2 password hashing algorithm

https://argon2-cffi.readthedocs.io/

Better dates and times for Python

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

ASN.1 library with a focus on performance and a pythonic API

https://github.com/wbond/asn1crypto

Abstract syntax tree for Python with inference support

https://github.com/PyCQA/astroid

Tiny library to add async generators to Python 3.5

https://pypi.org/project/async_generator/

Timeout context manager for asyncio programs

https://github.com/aio-libs/async-timeout

Reference implementation of PEP 3156 (Asynchronous IO)

https://github.com/python/asyncio

AtomicLong type using CFFI

https://pypi.org/project/atomiclong/

Atomic file writes library

https://github.com/untitaker/python-atomicwrites