CalyxOS
CalyxOS is a smartphone operating system based on Android. It is developed by the Calyx Institute, as a free, open source alternative to mainstream Android releases. CalyxOS is based ultimately on the Android Open Source Project, but also "draws heavily" from LineageOS. It is intended to offer improved user control and privacy, while still offering ease-of-use. Some compromises in the regard are made, such as the optional inclusion of MicroG. (This enables the user to run some applications which are designed to be dependent on Google Play Services, by using open source and somewhat more trusted software in its place.) Essentially, it is designed to be convenient and offer a relatively smooth transition for its users, while drastically improving the privacy and security of the platform.[1]
CalyxOS mostly supports "Pixel" phones from Google, as well as Fairphone.[2]