I believe that the following cryptocurrencies can be added to this list: Bitcoin, Ethereum, Litecoin, Cardano, IOTA, Ethereum Classic and Ontology.
but if I think that the best coins in 2018 for investment are bitcoin and ethereum. because both of these coins have good potential to be as fast and the price increases are always fast even though these two coins are now down again. but with a short time these two coins will soar