It's not quite Cyanogenmod though, don't get your hopes up too high. It doesn't have the most critical stuff I liked, like blacklisting non-contacts.
That seems like a dialer feature, not an OS one.
I'm not sure how that affects my point? Which was that you'll be missing the feature when you use LOS. (Not to mention I don't know how true it is either... the blacklist page was very much in my OS settings.)
If it's a dialer feature then you can just install any dialer which provides it.
I believe that would be possible even if it were not a dialer feature in CM? Also, I did look around for dialers, but a lot of them seem to do "cloud" stuff of some sort, which I definitely don't want. I ended up finding a non-dialer program to do this, but even that was a pain, since most of them that I tried are either missing functionality or buggy in one way or another.
Oh. My. God. Thank you. Around about the S5/S7 era I stoppped flashing my phone every 5 minutes, but now with my S7 drinking battery fluid every minute of the day I've been wondering where CM had gone.