Here is the list of most useful general-purpose Python Packages which can greatly speed up your development task.
Requests: Make network calls in a human-readable format.
Arrow: Makes working with date-time in Python really fun.
Beautifulsoup: Efficient HTML parser, modify and extract any elements from HTML.
Newspaper: Extract metadata from a webpage.
Pillow: Kind of Photoshop for Python, makes image editing in Python really easy.
Bpython: Very useful Python shell, it provides code completion, parameter lists, documentation to quickly prototype an idea.