I remember the most popular being Litecoin but what about now?
Here in the current time you can't say that a particular coin is more profitable than other because in the current many altcoins have Competition to rise in the market .
Here in my opinion fee of the coin which have the stability to increase demand and price in the future are below .
1) BTM coin , it has a good trading average daily in the Poloniex and Nova exchage but still prices are not much high( around 30k Satoshi)
2) Ripple , recently it got support by about 11 to 12 banks in the world for the Foreign countries money exchage platform .
3) Posw , this coin is the official coin of poswallet , so it's demand is really going increasing , I made Profit with this altcoin about 0.6btc in the last week .
4) Dgb , the segwit will came of this wallet and will become powerful in the future like the ETH , Currently price is very low , so better to buy some lakh coin .
5) Pak coin , this altcoin has the price range from 80 Satoshi to 300 Satoshi , so buy this altcoin when it is at the price of 100 Satoshi and then you can easily sell it at the 150 satoshi Because 150 Satoshi is a normal price rise per week for this coin .
Beside of these the most popular are Putin , creva , money , ETH , dash , EDR etc these has good support by the millionaire .