To find all Python packages, we can go to https://pypi.python.org/. The following screenshot shows the top part of the website. As of February 22, 2018, there are 130,230 packages available:
To find the packages we want, just click Browse packages and use keywords. For example, after entering Data Science, we will see the following results:
From the previous screenshot, we can see three columns: the first one gives the name of the package; the second one is called Weight, which can be viewed as the popularity index; and the last one offers a short description. The related URL is https://pypi.python.org/pypi?%3Aaction=search&term=data+science&submit=search.