OBO Foundry - The Open Biological and Biomedical Ontology Foundry is both a community for developing and a repository of interoperable ontologies for the biological sciences.

Symptom Ontology - The symptom ontology was designed around the guiding concept of a symptom being: "A perceived change in function, sensation or appearance reported by a patient indicative of a disease." Understanding the close relationship of Signs and Symptoms, where Signs are the objective observation of an illness, the Symptom Ontology will work to broaden it's scope to capture and document in a more robust manor these two sets of terms. Understanding that at times, the same term may be both a Sign and a Symptom.

Pathogen Transmission Ontology - The Pathogen Transmission Ontology (TRANS) describes the tranmission methods of human disease pathogens describing how a pathogen is transmitted from one host, reservoir, or source to another host. The pathogen transmission may occur either directly or indirectly and may involve animate vectors or inanimate vehicles. TRANS is available under CC0 license.

OBO ROBOT Tool - ROBOT is a tool for working with Open Biomedical Ontologies. It can be used as a command-line tool or as a library for any language on the Java Virtual Machine.

DO.utils - DO.utils is an R package that assists biomedical resource creators and maintainers in Assessing Resource Use & Impact from published literature and additionally supports analysis, maintenance, and publication of the Human Disease Ontology and this website. Online documentation of functions and tutorials are available at diseaseontology.github.io/DO.utils.