Look for the undervalued altcoins at this moment but make sure that they are within the top 50 numbers. I mean the rank is important as it decides how much volume is coming to them daily. This increases the trust over the project and you are at least sure that you wont be getting scammed. As far as I know any coin from the Top 50 would do great in th coming future. The number one reason to buy them is they are at discounted rate for now and thus whenever they will come back to normal position by that time you will have nice profits.
For your consideration there are some coins such as IOST, SIACOIN, IOTA, ADA, XRP, NEM etc, Do add ETH as it is prime coin.