There are some references that you can make a good reference if you are going to invest in altcoin, one of which you can see at
https://coinmarketcap.com/there you will see a very good altcoin ranking that you can make an investment
yes it can make it easier for you to know which Altcoin is good and has great potential. besides that you have to frequently evaluate the movements of Altcoin so that you know which ones can grow faster, and maybe there are still other things that can make it easier for you to know the good and potential Altcoin. now the market is still bad so coins that have great potential are also low in value, maybe they will rise again because coins are potentially strong so they can increase.
Using this as reference and continue learning about potential coins to invest with, there's a lots of project which can be buy as an assets holding for much longer time until the pumped happen, you can check all the details and news about those top coins safer to say that reading and monitoring current movements can give you good basis to what coin to buy.