Chemical Entities of Biological Interest
Dictionary of molecular entities focused on small chemical compounds. 60,000+ entities with structures and roles.
Visit WebsiteBrowse the tree, filter it, or click any class to see just its corner of it.
Where this one tends to earn its keep.
Chemical compound annotation in biology
Drug-target interaction databases
Metabolomics data annotation
Chemical safety and toxicology databases
I haven't checked this label against the actual licence text — it's the catalogue's original guess. Check the ontology's own site before you rely on it.
Others worth a look in Life Sciences.