I guess you mean the assets to build in your portfolio, well, it depends first on how much of money that you intend investing in the current market, if the money is not so much for diversification, you can just pick Bitcoin and Ethereum, because certainly, these two coins will surely give you the services you required i.e. they do great jobs for investment and they are perfect coins to consider for using as payment method.

If you have enough money for diversification, what I usually do is to check on Binance exchange and look at the top altcoins that are performing well, these coins at the top on this exchange will definitely do well all the time, and most especially, during the altcoins bull run when the time comes.