* [pycurl](https://github.com/pycurl/pycurl) - network library (binding to [libcurl](http://curl.haxx.se/libcurl/))
* [urllib3](https://github.com/shazow/urllib3) - Python HTTP library with thread-safe connection pooling, file post support, sanity friendly, and more.
* [lxml](http://lxml.de) - effective HTML/XML processing library. Supports XPATH. Written in C.
* [cssselect](https://pythonhosted.org/cssselect) - working with DOM tree with CSS selectors
* [pyquery](http://pythonhosted.org//pyquery/) - working with DOM tree with jQuery-like selectors
* [BeautifulSoup](http://www.crummy.com/software/BeautifulSoup/bs4/doc/) - slow HTML/XMl processing library, written in pure python
* [html5lib](http://html5lib.readthedocs.org/en/latest/) - building DOM of HTML/XML парсинг according to [WHATWG spec](url=http://www.whatwg.org/). That spec is used in all modern browsers.
* [feedparser](http://pythonhosted.org/feedparser/) - parsing of RSS/ATOM feeds.
* [Bleach](http://bleach.readthedocs.org/en/latest/) - cleaning of HTML (requires html5lib)
*Libraries for parsing and manipulating specific text formats.*
* General
* [tablib](https://github.com/kennethreitz/tablib) - A module for Tabular Datasets in XLS, CSV, JSON, YAML.
* Office
* [python-docx](https://github.com/python-openxml/python-docx) - Reads, queries and modifies Microsoft Word 2007/2008 docx files.
* [xlwt](https://github.com/python-excel/xlwt) / [xlrd](https://github.com/python-excel/xlrd) - Writing and reading data and formatting information from Excel files.
* [XlsxWriter](https://xlsxwriter.readthedocs.org/) - A Python module for creating Excel .xlsx files.
* [xlwings](http://xlwings.org/) - A BSD-licensed library that makes it easy to call Python from Excel and vice versa.
* [openpyxl](https://openpyxl.readthedocs.org/en/latest/) - A library for reading and writing Excel 2010 xlsx/xlsm/xltx/xltm files.
* [Marmir](https://github.com/brianray/mm) - Takes Python data structures and turns them into spreadsheets.
* PDF
* [PDFMiner](https://github.com/euske/pdfminer) - A tool for extracting information from PDF documents.
* [PyPDF2](https://github.com/mstamy2/PyPDF2) - A library capable of splitting, merging and transforming PDF pages.
* [ReportLab](http://www.reportlab.com/opensource/) - Allowing Rapid creation of rich PDF documents.
* Markdown
* [Python-Markdown](https://github.com/waylan/Python-Markdown) - A Python implementation of John Gruber’s Markdown.
* [Mistune](https://github.com/lepture/mistune) - Fastest and full featured pure Python parsers of Markdown.
* YAML
* [PyYAML](http://pyyaml.org/) - YAML implementations for Python.
* [NLTK](http://www.nltk.org/) - A leading platform for building Python programs to work with human language data.
* [Pattern](http://www.clips.ua.ac.be/pattern) - A web mining module for the Python. It has tools for natural language processing, machine learning, among others.
* [TextBlob](http://textblob.readthedocs.org/) - Providing a consistent API for diving into common NLP tasks. Stands on the giant shoulders of NLTK and Pattern.
* [jieba](https://github.com/fxsjy/jieba) - Chinese Words Segmentation Utilities.
* [SnowNLP](https://github.com/isnowfy/snownlp) - A library for processing Chinese text.
* [loso](https://github.com/victorlin/loso) - Another Chinese segmentation library.
* [genius](https://github.com/duanhongyi/genius) - A Chinese segment base on Conditional Random Field.
* [langid.py](https://github.com/saffsd/langid.py) - Stand-alone language identification system.
* [Korean](https://korean.readthedocs.org/) - A library for [Korean](http://en.wikipedia.org/wiki/Korean_language) morphology.
## Downloader
*Libraries for downloading.*
* [s3cmd](https://github.com/s3tools/s3cmd) - A command line tool for managing Amazon S3 and CloudFront.
* [s4cmd](https://github.com/bloomreach/s4cmd) - Super S3 command line tool, good for higher performance.
* [youtube-dl](http://rg3.github.io/youtube-dl/) - A small command-line program to download videos from YouTube.
* [you-get](http://www.soimort.org/you-get/) - A YouTube/Youku/Niconico video downloader written in Python 3.
* [WikiTeam](https://github.com/WikiTeam/wikiteam) - Tools for downloading and preserving wikis.
* [subliminal](https://github.com/Diaoul/subliminal) - Library and command line tool to search and download subtitles.
* [threading](http://docs.python.org/2.7/library/threading.html) - standard python library to run threads. Effective for I/O-bound tasks. Useless for CPU-bound tasks because of python GIL.
* [multiprocessing](http://docs.python.org/2.7/library/multiprocessing.html) - standard python library to run processes.
* [celery](http://www.celeryproject.org/) - An asynchronous task queue/job queue based on distributed message passing.
* [concurrent-futures](https://docs.python.org/3/library/concurrent.futures.html) - The concurrent.futures module provides a high-level interface for asynchronously executing callables.
## Asynchronous
*Libraries for asynchronous networking programming.*
* [asyncio](https://docs.python.org/3/library/asyncio.html) - (Python standard library in Python 3.4+) Asynchronous I/O, event loop, coroutines and tasks.
* [Twisted](https://twistedmatrix.com/trac/) - An event-driven networking engine.
* [Tornado](http://www.tornadoweb.org/) - A Web framework and asynchronous networking library.
* [pulsar](https://github.com/quantmind/pulsar) - Event-driven concurrent framework for Python.
* [diesel](https://github.com/jamwt/diesel) - Greenlet-based event I/O Framework for Python.
* [urllib.parse](https://docs.python.org/3/library/urllib.parse.html) - interface to break Uniform Resource Locator (URL) strings up in components (addressing scheme, network location, path etc.), to combine the components back into a URL string, and to convert a “relative URL” to an absolute URL given a “base URL.” (stdlib)
* [tldextract](https://github.com/john-kurkowski/tldextract) - Accurately separate the TLD from the registered domain and subdomains of a URL, using the Public Suffix List.
* [scrapely](https://github.com/scrapy/scrapely) - Library for extracting structured data from HTML pages. Given some example web pages and the data to be extracted, scrapely constructs a parser for all similar pages.
* [Crossbar](https://github.com/crossbario/crossbar/) - Open-source Unified Application Router (Websocket & WAMP for Python on Autobahn).
* [AutobahnPython](https://github.com/tavendo/AutobahnPython) - WebSocket & WAMP for Python on Twisted and [asyncio](https://docs.python.org/3/library/asyncio.html).
* [WebSocket-for-Python](https://github.com/Lawouach/WebSocket-for-Python) - WebSocket client and server library for Python 2 and 3 as well as PyPy.
* [pycares](https://github.com/saghul/pycares) - interface to c-ares. c-ares is a C library that performs DNS requests and name resolutions asynchronously
* [OpenCV](https://github.com/Itseez/opencv) - Open Source Computer Vision Library.
* [SimpleCV](https://github.com/sightmachine/SimpleCV) - Concise, readable interface for cameras, image manipulation, feature extraction, and format conversion (based on OpenCV).
