I am building an ontology-processing tool and need lots of examples of various owl ontologies, as people are building and using them in the real world. I'm not talking about foundational ontologies such as Cyc, I'm talking about smaller, domain-specific ones.
6 Answers
There's no definitive collection afaik, but these links all have useful collections of OWL and RDFS ontologies:
- schemaweb.info
- vocab.org
- owlseek
- linking open data constellation
- RDF schema registry (rather old now)
In addition, there are some general-purpose RDF/RDFS/OWL search engines you may find helpful:
Ian

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My go-to site for this probably didn't exist at the time of the question. For latecomers like me:
I wish I'd found it much sooner!
It's well-groomed, maintained, has all the most-popular ontologies, and has a good search engine. However, it doesn't include some specialized collections, most notably, (most of?) the stuff in OBO Foundry.

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Within the life-science domain, the publically abvailable ontologies can be found listed on the OBO Foundry site. These ontologies can be queried via the ontology lookup service or the NCBO's Bioportal, which also contains additional resources.

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