Looking at the top few packages:
* simplejson is the upstream for the json module in stdlib which people install since it gets performance updates first
* requests
* six: the most common library used to bridge the Python 2/3 transition
* virtualenv: near-ubiquitous development tool (it allows you to maintain a separate Python environment for each project to avoid cross-talk, and is also used by popular testing tools like tox which run your tests under a variety of Python versions)
* distribute: a few years back, the stdlib setuptools module was forked for a major overhaul. That's since been merged back in but many packages still reference it, particularly in older releases
* boto: AWS client library, used by the official awscli tool
* pip: Python package installer, now bundled with Python but updates & older versions of Python use the PyPI version
As a proxy, check out the download counts on this tracker using data from the PyPI, where the vast majority of Python packages are installed from:
https://python3wos.appspot.com/
Looking at the top few packages: * simplejson is the upstream for the json module in stdlib which people install since it gets performance updates first * requests * six: the most common library used to bridge the Python 2/3 transition * virtualenv: near-ubiquitous development tool (it allows you to maintain a separate Python environment for each project to avoid cross-talk, and is also used by popular testing tools like tox which run your tests under a variety of Python versions) * distribute: a few years back, the stdlib setuptools module was forked for a major overhaul. That's since been merged back in but many packages still reference it, particularly in older releases * boto: AWS client library, used by the official awscli tool * pip: Python package installer, now bundled with Python but updates & older versions of Python use the PyPI version