Ionic's is probably one of the best date+time combo (other examples are always strong in one and terrible in the other, time being the thing that often gets short shrift)
Interestingly it lets see both the iOS and Material Design versions of the component.
iOS has a strange combination of arrows to handle the month: right to expand the months dialog, down to close it. It took me a while to understand that the down arrow would bring me back to the calendar. Why not right and left? Maybe it is how it works on a Mac too.
MD and anything else I remember has a down arrow to expand and an up arrow to close.