I’ve just added PyChem-Pro to the list of cheminformatics toolkits https://macinchem.org/2023/02/17/open-source-cheminformatics-toolkits/
PyChem is a desktop chemistry application and Python library that combines molecular visualization (like PyMOL) with cheminformatics primitives (like RDKit). Unlike most tools in the space, PyChem is pure Python with NumPy. There is no C++ extension, no RDKit dependency, no OpenBabel binding. Every feature — SMILES parsing, 3D coordinate generation, force field optimization, descriptor calculation, Shrake-Rupley SASA, ring perception, protein cartoon rendering — is implemented from scratch and readable end-to-end.