- Jolla/Sailfish is still alive, but not doing particularly well (I'm typing on one.)
- Firefox failed
- Ubuntu failed (I hear a community is still continuing with the SW, but not sure whether it runs on any phone HW)
I'm sure I missed something, but I'm sure I did not miss any real good ones.
Yes, it's a community effort and yes it does run on actual hardware.[0][1] A Nexus 5 is probably most stable. All the devices that were originally launched by companies in cooperation with Canonical, are also still supported. In addition, AFAIR Ubuntu touch should run on any android devices that Halium[2] supports (the purpose of Halium is for projects like KDE Mobile, Ubuntu Touch, PureOS (?) etc. to share the code needed for "normal" (GNU) Linux to run on Android devices).
[0] https://ubports.com/devices/promoted-devices
[1] (javascript needed) https://devices.ubuntu-touch.io/
2nd most used mobile os in India, and I want to say it has 1% global market share, but I can’t back that up. But I’d say you missed a pretty good one :)