Here are some of my favorite small-cap coins, that have the potential to go up in price significantly in 2019.
BLU-censorship resistant coin that you can use via Bluetooth. Plus you get a staking reward for holding the coin offline.
BAY-One of the only cryptos with a practical approach to smart contracts in my opinion. You can think of it as an escrow platform, where BAY (held in a smart contract escrow is used by both parties as the middleman).
BURST-Uses empty hard drive space for mining (something called proof-of-capacity). This allows the crypto to be inherently decentralized and fee-less, as mining is done with empty hard drive space - meaning its much more efficient energy consumption wise. Keep an eye out on this one.