The compiled-in module names are in sys.builtin_module_names. For all importable modules, see pkgutil.iter_modules.
Run these in a clean virtualenv to get (almost) only the modules that come with Python itself.
Note that a “popularity poll” will necessarily include modules that use old, discouraged naming conventions because they were written before today's guidelines were put in place, and can't change because need to be backwards compatible. It might be useful for something, but not for answering best-practice questions such as “How should I name my functions?”. For that, see the PEP8, the Python style guide, especially the “Naming Conventions” section.
Answer from Petr Viktorin on Stack OverflowHow to get a list of built-in modules in python? - Stack Overflow
What is a built-in Python module you use all the time but ...
Any Guide on python built-in modules?
The Python Module of the Week site gives an overview of many of the modules in the standard library, with some example code. The associated book might be worth looking at, but I've never used it.
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The compiled-in module names are in sys.builtin_module_names. For all importable modules, see pkgutil.iter_modules.
Run these in a clean virtualenv to get (almost) only the modules that come with Python itself.
Note that a “popularity poll” will necessarily include modules that use old, discouraged naming conventions because they were written before today's guidelines were put in place, and can't change because need to be backwards compatible. It might be useful for something, but not for answering best-practice questions such as “How should I name my functions?”. For that, see the PEP8, the Python style guide, especially the “Naming Conventions” section.
How about this? Though, this gets a list of built-in functions and variables rather than modules...
dir(__builtins__)
help('modules') will give you a list of all modules, according to How can I get a list of locally installed Python modules?. Not a list of strings, though.