Android - Android is an open source mobile operating system initially released by Google in 2008 and has since become of the most widely used operating systems on any platform.
MIUI - Xiaomi MIUI Official Global Site. MIUI is a customized Android ROM developed by Xiaomi for smartphones and tablets. MIUI Forum offers ROM downloads for 251 devices including Mi 6, Mi MIX 2, Redmi Note 4 and others.
CalyxOS - Privacy-focused operating system for smartphones based on Android and microG
Sailfish OS - At the heart of Jolla is Sailfish OS, the independent mobile operating system offering an alternative to the existing dominant systems. Sailfish OS is the perfect solution for country ecosystem and corporate mobile projects, or for consumer devices.
LineageOS - Operating system for smartphones and tablet computers, based on the Android
PureOS - A user friendly, secure and freedom respecting OS for your daily usage