Consider LineageOS

Lineage OS is a community fork of CyanogenMod (which we used to recommend but removed as of #1588 per discussions in #654 (closed), #726 (closed), and #1005 (closed)) that seems to have the support of a lot of the original community and developers that were disenfranchised by the commercial direction taken by Cyanogen Inc. The repositories are looking good and it seems like this lives up to the previous standards we held Cyanogen too before the commercialization hit. It's trajectory seems quite promising.

I'm not sure yet whether we should recommend it, but certainly we should be keeping an eye on it and considering the pros and cons of recommending it in light of the return to open source roots.

See also tangentially related discussions at #1600 (closed) for Replicant, #1524 (closed) for Copperhead, and #903 (closed) for OMNIrom.