BTC, ETH - must have. XRP, XLM, EOS, TRON, IOTA, NEO.
Also several coins from exchanges - BNB, KCS, BIX etc.
VET also looks perspective.
What about Spectrecoin (XSPEC)? Have anyone heard about it? It looked interesting fo me and I am thinking to buy it.
As I know the mainnet will launch in the beginning of 2019.