LuneOS

LuneOS is a mobile operating system (OS) based on the Linux kernel and currently developed by WebOS Ports community. With a user interface based on direct manipulation, LuneOS is designed primarily for touchscreen mobile devices such as smartphones and tablet computers. The OS uses touch inputs that loosely correspond to real-world actions, like swiping, tapping, pinching, and reverse pinching to manipulate on-screen objects, and a virtual keyboard.
LuneOS is the open source successor for Palm/HP webOS where the user interface is rebuilt from scratch by using the latest technologies available (Qt 5.15.0 / QML, Qt WebEngine, etc). It is not intended to compete with iPhone or Android on features. All devices can have a LuneOS port if they have a CyanogenMod / LineageOS ROM available that works. LuneOS uses the minimal Android System Image that is created using Halium which in turn is based upon CyanogenMod / LineageOS.
Currently, the system is still in alpha, with some internal hardware not supported and some applications still buggy. It can be updated without a reinstall. It has the feel of the webOS formerly used on Palm and HP hardware, including a cards-based multitasking system and Universal Search. It has been described as "a niche mobile operating system maintained by enthusiasts".