I think ethereum will be the most pump cryptocurrencies coming 2019. Ethereum is currently a little above $210 and that means it is currently undervalued because some were this year it went above $1400.
Litecoin will also perform very well next year as it is also currently undervalued and if you can take the risk and buy at $50 you are going to make good profits in future if it get to the  level it was last year ending.