In practical terms, yes. There are a very few. Not that their teams wouldn't trade them for the right price, but that no one would either have, or be willing to pay that price.
McDavid is obviously the first one to come to mind. Eichel would be another one, but he is probably going to be traded this off-season. Matthews is another that you just can't imagine the Leafs trading. But what about in another couple of years if he refuses to extend with them? Cale Makar is still only 22 and he scored over a ppg this year. It would be pretty tough to get him. There must be a few more, but not all that many.
I often say that anyone can be traded for a price and I believe that. But not without exception.
In practical terms,
almost anyone can be traded. That is, if a team needs to fill a position, as the Jets do, they can do it by trade if they are willing to pay. They are not limited to the short list of players who are being shopped. They are limited by the price.
The difficulty is greater for established players. That's why I have been looking at Moritz Seider. An already well developed prospect, but not yet established in the NHL. I expect that DRW have big plans for him, so it would require something of an overpay to spring him loose.
We have the assets to offer that - we just have to be willing to part with them. We have Perfetti, a prospect on a similar level playing at a similarly important and hard to fill position. Detroit has a need at every position so position shouldn't make much difference. DRW aren't looking to make the deal so they need to be given more than an even up deal to get them to move. They were planning on adding a big, physical Dman, so I also give them Stanley. To give it the final push to get it done, I give them our 1st. IMO it is now a clear overpay, an offer they can't refuse. Worth it to us because we can afford it and because it fills our big hole at RD.
People here have already fallen in love with Perfetti, and for good reason. But you have to give to get and we need that 1RD a lot more than we need another top 6 F and a lefty at that.
Edit: To circle back to the original point, Seider is one who people say is not available. I think he becomes available for that offer.