I have updated the page list open source cheminformatics toolkits.
To date it includes:-
OpenBabel (http://openbabel.org/wiki/Main_Page)
RDKit (http://www.rdkit.org)
CDK (https://cdk.github.io)
Indigo (http://lifescience.opensource.epam.com/indigo/)
OpenChemLib (https://github.com/Actelion/openchemlib/)
ChemDoodle Web Components (https://web.chemdoodle.com)
Kekule.js (http://partridgejiang.github.io/Kekule.js/index.html)
WebMolKit (https://github.com/aclarkxyz/web_molkit)
Chempy (https://pypi.org/project/chempy/)
If you know of any I’ve missed please let me know.