Best year, best strike

There really isn't a simple, straightforward answer to your question. That's because it's pretty unusual, I might even say rare, for a given date/mint issue to be known for the majority of them to be very well or fully struck.

However, it is downright common for there to be a few examples of a given date/mint from almost any type to be found very well or fully struck.

And there is even a type or two where there are never any examples to be found fully struck.

For example, you mentioned the '81-S Morgan, somebody else mentioned the '80-S Morgan, as being known to be very well or fully struck. This is quite true, but so is the '82-S Morgan. And all 3 of them are graded to a stricter standard than other Morgans in regard to quality of strike.

An example of a different kind, someone mentioned the '21 Peace for being very well or fully struck. Sorry, but this just isn't true. Quite the opposite in fact, the '21 Peace is never found fully struck. And even examples that have what might be called a good strike are downright scarce. The '21 Peace is notorious for being weakly struck.

And Jefferson nickels, you'd be hard pressed to find a fully struck Jefferson nickel, even from among most of the modern versions. And even from among Proofs. From the most modern Jeffs, after they had lowered the relief to where it was almost flat, yeah you might find a few.

As I mentioned above, across the spectrum of all coins there are usually some examples found very well or even fully struck. But they are not limited by a given date/mint, but instead can be found from a variety of dates/mints for the type. The reason for this is because quality of strike for any given issue is determined by basically 5 things: coin design, proper die alignment, proper die spacing, proper strike pressure, and fresh dies. Get all 5 of those things right and you'll usually end up with a very well or fully struck coin. But get just 1 of them wrong - and you won't.

And there is even more to consider beyond that. This is because with most of our coins there changes made to the design (to the hubs), sometimes several times, during the life of the given type. And when there are changes to the design you can't compare a pre-change date to a post-change date because changes to the design alter the way a coin strikes up. Think of the Lincoln cent for example, there were so many changes to the design of the Lincoln cent that it gets kind of hard to count them all. The Buffalo nickel is similar in that regard, just not to that extent. What I'm trying to point out is that you can't compare a 1909 Lincoln to a 1940's Lincoln because there just isn't any comparison - they are two different coins ! Same with 1913 Buff and a 1938 Buff.

So when you are trying to compare quality of strike you can only do so with examples known to be from the same hub design. That said there were far fewer hub design changes pre 1900 than there were post 1900. And on early coinage they didn't even have or use hubs.

The reason I'm pointing all of this out is because the list you are compiling in post #19, it's not quite accurate, at least in regard to answering your original question. There are a couple of other examples like the early S mint Morgans where pretty much all examples are known to be very well or fully struck. But only a couple, and like the Morgans they are graded to stricter standards than the rest of their type. But it's been so long since I even thought about them that I cannot recall what they were exactly off the top of my head. But I seem to recall that they were gold. Pretty sure you can find the answer in the Encyclopedia of US Gold Coins by Garret and Guth.

Someone else asked -

Yes, there are even some examples of coins with clash marks that are fully struck. That is because the two things, clash marks and quality of strike, sometimes don't have anything to do with each other. That said, there are other times when clash marks can diminish the quality of strike, but only when the die clash has partially destroyed part of the design. So the answer is it can go either way.

 

But that is exactly the point I am making - there are hardly coins that meet that qualification. There are a few, just not a lot of them.