Bambi: BAyesian Model-Building Interface (BAMBI) in Python.
calibr8: A toolbox for constructing detailed observation models to be used as likelihoods in PyMC.
CausalPy: A package focussing on causal inference in quasi-experimental settings.
SunODE: Fast ODE solver, much faster than the one that comes with PyMC.
pymc-learn: Custom PyMC models built on top of pymc3_models/scikit-learn API