I don't have a list of them and mostly don't use them myself, but a number of third party things already exist. You will probably get more helpful and enthusiastic replies if you ask about such options.
HN policy is intentionally conservative. They don't like changing things much. But the membership also has tremendous enthusiasm for providing third party solutions, usually for free. HN staff appears to be happy to tolerate this ad hoc ecosystem and I'm not aware of them getting cranky about it.
Edit: I absolutely suck at finding such things, but here's an old discussion to try to get you started:
https://news.ycombinator.com/item?id=15310291
They come and go. Since it's an old discussion, some of the services listed may be defunct.
Unfortunately, it's impossible to search this list except by scrolling through it.
Ccould a "read articles" possibly be done through the use of cookies on the users browser, rather than being stored on HN servers?
The other dimension is it’s a low priority relative to the invisible work on HN that makes HN what it is because of what doesn’t surface like spam and flamethrowers and blatant astroturfing and injection attacks.
If it’s really important, why not hack something up yourself?