The current version of /e/ mobile OS includes free software and a single-login setup that comes very close to the UI experience when you first signup to Google Android or Apple iOS devices. See the list of available devices at https://gitlab.e.foundation/e/wiki/en/wikis/devices-list

/e/ is a non-profit project, in the public interest. We build open-source mobile operating systems that respect users’ data privacy. We’re an international core team of experienced entrepreneurs, developers and designers, and a growing community of contributors.

F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device. It is particularly helpful on Android devices to replace or augment the Google Play store, and when de-googlifying such mobile devices.

LineageOS is a free and open-source operating system for various devices, based on the Android mobile platform. It originated when the CyanogenMod project was stopped.