I think GitHub has had this feature for a while but I just noticed it
today. If you click the "insights" tab on the GitHub page, you can get
a list of all the repos and all the packages on GitHub that depend on
SymPy.
https://github.com/sympy/sympy/network/dependents?dependent_type=PACKAGE
According to the page, there are 6651 repos and 261 packages that
depend on SymPy.
I think the repos search only parses requirements.txt, so it's only a
fraction of the total repos on GitHub that have Python code that
imports SymPy (just searching GitHub for "sympy" gives over 466k repos
that contain the word in code).
I'm not sure what makes something a "package" in their list. Maybe
they detect if it is on PyPI?
Aaron Meurer