There are 2 repositories under computational-social-choice topic.
Python implementations of approval-based committee (multi-winner) voting rules
pref_voting is a Python package that can be used to study and run elections with different preferential voting methods (graded voting methods and cardinal voting methods are also included for comparison).
A collection of simple algorithms for fair division of indivisible items
All the Python scripts for the paper Local Diversity of Condorcet Domains