Ruby black would have been an individual color in the US market. Otherwise it was black sapphire, jet black, or carbon black (carbon only available with M Sport).
The interior options would be black, mocha, terra, canberra beige, or 'ivory white' - which is basically the same as oyster, though it wasn't called that on the F15.
Anyhow, sounds like you might be looking for a private sale, but you might try checking out the BMW CPO page, especially since you're looking for a fairly newer model. Tons of lease returns listed there. I've found my last 3 BMWs on this site, however I will say their filters have gone the crap recently. You can no longer filter on model to narrow down search results
So right now I see 109 2017/2018 black M sports (you can filter on packages and color), but that includes all models - 40e, 35i, 35d, 50i, and X5M. If they hadn't removed the model filter you can quickly see just the 35d models.
Good luck w/ your search.
https://cpo.bmwusa.com