In the wake of the ongoing US-Huawei-Google tussle, many Android enthusiasts are wondering about the different alternative phone operating systems that are out there. We have Apple’s iOS at our disposal, but the cost of owning an iPhone makes it an impossible choice for many (and for me its restrictions were just too much).
But here is a list of alternatives of which LineageOS probably has the widest support for different devices at https://fossbytes.com/android-alternatives-open-source-linux/
#android6 Open Source Android Alternative Operating Systems For Mobiles
I've created a list of other Android alternatives that are being developed or being used in mobile devices. The options that have been included in this list are open source, so any developer can grab the code and fork it to create something new for free. Huawei is itself creating its own operating system but I haven't included it on this as the details are scarce.