I think the best coins to get involved with in 2018 are going to be privacy coins and coins that focus on faster transactions with big block sizes and perhaps even zero fees. Basically the things that bitcoin struggle with other coins will pick up the slack and these coins will do quite well in my opinion.
Following on this, I feel like DeepOnion and Komodo have large growth potential, both privacy coins (although deeponion is a much smaller market cap), so I'd try either.
don't forget with bcn because bcn is adopted from monero which is offering privacy for every people and the fees of bcn is not too big. the price now is still in under estimate but I think it will going to increase soon. deeponion and komodo is good too if you need to invest for a long term and I think deeponion have a small fee too like bcn. besides that, there is another cheap coin that we can invest which is rdd and this coin is undervalued too.