A notable mention is https://ubports.com/en/ which is different from postmarketos in a sense that ubports uses old kernels with heavy patches. That means: good support for things, but difficult future.
PostmarketOS uses the newest kernels and tries to integrate their patches into mainline kernel, so that the reliability is maintained with all kernel developers.
Are you saying I could get Linux running on my Fairphone 3+?
Mind you, yeah, 3G switch off would then make life difficult…
Sure. Looks like on Ubuntu Touch the only thing not working is the fingerprint reader
https://devices.ubuntu-touch.io/device/fp3/
The OS in general isn’t ready for daily use though. It’s maybe doable if all you need is text, calls, camera, and a browser. And the calls only work in some countries. But it’s fun to play with.