Schema.org¶
I keep this around for structured data and for naming things in apps without inventing yet another private taxonomy that falls apart the first time a non-Western name shows up.
Schema.org's Vocabulary shows up as RDFa, Microdata, or JSON-LD on the page. Under the hood it is types, properties, and relations between entities, and you can extend it if the core set is not enough.
When I model something in a database or an API, I still borrow property names and shapes from here. It is rough around the edges in places, but it is battle tested by the fact that search engines and half the web actually consume it.
Example: Person - Schema.org Type.
The Schema.org vocabulary uses givenName and familyName instead of firstName and lastName, since "first" and "last" are not universal. That is a small detail, but it keeps you from making wrong assumptions.