Windows’s, well, windows as a object/concurrency system are one (even if the Win32 transition to multithreading is IMO conceptually botched). The actor model admittedly already existed at that point, but Mark Miller et al.’s work on E (the only other source I know for having separate synchronous and asynchronous sends) hadn’t even started at that point. (There are innumerable papers on various versions of actors, though, so I might have missed it.)

COM aggregation is another. It would probably have been much more successful had they used fat pointers, and there are a couple of old papers pointing this approach is a viable way to do implementation (as opposed to interface) inheritance. But I know of no precedent in the literature for the inside-out way WinRT builds its allegedly more conventional inheritance mechanism on it. (I guess I would’ve referenced BETA if I were writing a paper on it?)

DCOM’s “causality IDs” for reentrancy control are yet another. You can basically have calls to your object guarded by a recursive mutex whose ownership is passed along with any remote calls that that object itself makes. I’m not sure they are a good idea (recursive mutexes are perilous in the simplest of situations, and this is most definitely not one of those), but I’m almost certain it’s an original one.

That’s it, for now, but I’m almost certain I could find more, if only I knew where to look.