I really like OpenAPI in conjunction with openapi-fetch to create a typed interface for frontends/tests/etc to leverage. I especially like deleting the manual types that get strewn around frontends with inaccuracies, bespoke class names and unnecessary property names/types transformations.
As a JSON Schema TSC member, I consulted with various organisations on large scale JSON Schema use, which is where things get truly interesting (>8000 complex interconnected schema data models) though all of them are sadly closed-source.
I wouldn't work without these tools anymore!