Not an app, but for the ones interested in following specific hacker news posts, there's the unofficial Hacker News RSS feeds.
https://github.com/cheeaun/awesome-hacker-news#android
It's really a personal preference. Try them and see which one fits you the best.
My only complaint is that you can't edit comments you've recently made from the app, you gotta go on the website.
I used to be, but for me it's no longer available from the app store. Is it geolocked these days?
I don't think so. It might have been delisted as I don't see it either. Regardless, it's OSS so you can get it from the GitHub repo. https://github.com/hidroh/materialistic
Hacki is pretty good.
I use fdroid apps whenever possible... This was the only one on fdroid as of a few months ago.