I just can't say about exact numbers but I think 2019 and 2020 will be really good for such next coins like Litecoin, Ripple and Ethereum. Altcoins started to rise up from New Year. Might be so good.
I agree with you about litecoin and ethereum.
Both coins have bigger plans for 2019. Anonymous transactions in litecoin and Constantinople on the ethereum.
the light will also reduce the reward by half this year, and the price charts indicate a long (in time) growth, so we expect growth, and the situation in the world is improving