- GrapheneOS, a de-googled fork of open source Android, has amazing privacy features while not compromising on proprietary services that you need to use, UX, or security.
- Glider is the best HN client you can find on Android that is also open sourced and on F-droid
- Proton has amazing VPN, mail, and cloud storage services that are still a bit lackluster in features when it comes to applications (Linux VPN GUI is bad, no cloud storage app or sync) but very capable, affordable, and promising for the future
- Wikipedia. I don't know if this fits exactly, but it has been so useful not only to me in research and studying, but also to voice assistants, web browsers, documentarians, students and countless others.
I don't love the way Glider displays the favicon for the website of each post. I find it makes the UI really noisy. Other than that, it's a great client. I also like Hews.
- Glider is the best HN client you can find on Android that is also open sourced and on F-droid
- Proton has amazing VPN, mail, and cloud storage services that are still a bit lackluster in features when it comes to applications (Linux VPN GUI is bad, no cloud storage app or sync) but very capable, affordable, and promising for the future
- Wikipedia. I don't know if this fits exactly, but it has been so useful not only to me in research and studying, but also to voice assistants, web browsers, documentarians, students and countless others.