I maintain a relatively new one called HN Pro [1]. It
was rated 5/5 on the iOS App Store until Friday's HN updates broke parsing, but that bug has since been fixed. I'd love more folks to try it out and provide some feedback.
The app is privacy-first; no tracking or analytics SDKs are installed. You can log in with your username, upvote, downvote, and comment. The idea is to provide as close to the web experience as possible in terms of "feel" and not to add any extra flair.
I'd love to work more on it, so if folks have any ideas with respect to monetization or marketing, I'm all ears! FWIW, I've been recently toying around with the idea of just open-sourcing it and making it donation-only. Haven't really come to any conclusions yet.
Also, I'm aware of some UX/UI issues with the latest update—it had been a while since the previous build and recent UIKit changes have created some wonkiness. :)
[1]: https://apps.apple.com/us/app/hn-pro/id1384303792