In the third quarter of this year the downward trend is very strong and that means buying altcoins is the right time to hold for the long term, but that way buying altcoins when this situation has to be careful not to be careless, because buying just any altcoins will only end at a loss, so it would be better to just buy altcoins that have high potential such as ethereum and altcoins below which have been very popular in the cryptocurrency market.
Yaps, for now, buying popular altcoin also looks pretty good. although the price tends to go down, I think that the potential of altcoin that is popular is far better than the newly developing ones. but, this only applies to those who can hold it in the long run.
of course if asking about the most popular altcoin has become common, such as ETH, BCH, LTC meter, BNB, and the rest you can see on coinmarketcap. these coins are the most potential altcoin. if you want to take risks, try investing in IEO, a new project because we don't know whether the price can be higher than the initial price, or dump.