It's difficult to choose the best altcoins to invest because all includes risk that you can take. Also, in order to benefit from those altcoins, you should consider the timeframe if how long you are going to hold your coins. At this moment, almost all altcoin is in a red market which is good to buy but always be careful to choose. The best you can do is check on the top 10 altcoins in coinmarketcap and then decide if you want to buy, hold and risk to that altcoins.