I'm not aware of any other OAuth provider libraries for Workers. Plenty of clients, but not providers -- implementing the provider side is not that common, historically. See my other comment:
Novelness is not a characteristic of interpolation, tho, it's about extrapolation. If you have plenty of clients and plenty of related stuff to the provider side, even if on on auth, then it could be considerably trivial for the LLM to interpolate on that field.
https://news.ycombinator.com/item?id=44164204