I haven't heard of anyone reverse engineering common schemas / parameters from existing APIs (I doubt the commonalities are really there) but there are projects

I haven't heard of anyone reverse engineering common schemas / parameters from existing APIs (I doubt the commonalities are really there) but there are projects like this one [0] which express schema.org types as JSON Schema objects suitable for use in OpenAPI. [0] https://github.com/tandfgroup/schema-oas https://github.com/tandfgroup/schema-oas