I think ethereum and ripple are two coins I surely want to hold in 2019 simply because these are some of the most popular crypto. Ethereum is considered as master of all smart contracts and its value increases with the release of every new token which is based on this platform. Its value can surely reach new heights in the future.
Ripple on the other hand is based upon the idea of global value transfer and has tremendous potential to change the global banking scenario. You can expect it's price to hit 5-6$ within 2-3 years.