Abbey Road - The Beatles
That was the last studio album the Beatles wrote and recorded as a band. Give an asterisk if you want since Let It Be was technically released after it (but most of it was recorded in pieces before Abbey Road, and several of the songs had even been released as singles before Abbey Road, so Let It Be seems more like a collection of songs pieced together to round out the band's history as they were breaking up rather than a proper studio album), but that's the first one that came to mind.
Personally I'd put it behind Revolver and I think general consensus is Sgt Peppers is their best? But Abbey Road is certainly in the conversation.
I am not sure there is a consensus anymore. When I was young, it felt like Sgt Pepper was the consensus, but has time has gone on, it feels like Revolver, Sgt Pepper and Abbey Road are all about equal across the board (which is highest almost depends on where you look). Personally, I dock Revolver just a tad because it has such a bland opener (Taxman), but it is otherwise fantastic.
The Police - Synchronicity
That might be the best pick here, as I think that is their best album by a wide distance.
I would say Pink Floyd's The Division Bell, but that only works if you don't count The Endless River (not sure you should).
The Endless River, to me, is similar to Queen's Made in Heaven in that it feels like an album of leftovers thrown together and released more than a real studio album, but that is splitting hairs. The Division Bell is great, regardless.