As we go into 2018 we will have 3 new additions to the Bitcoin family, including Bitcoin Gold, Bitcoin Cash, and the newest token to come on the 18th.

I think it's not certain.

Bitcoin Gold: On the first announcement, Bitcoin Gold seemed to be just some unconfirmed rumor - seems like the project has a bit more flesh on the bone now, but still I don't take it for granted until I can mine my own tokens and sell on some exchange.

SegWit2X vs Core: There is still some probability that there won't be a split, and also a good probability that only one of the chains will be considered alive in 2018.