I think the most favorite altcoin this year is Ethereum, Stellar and Monero. Ethereum is the queen of the market, for me it is always worth investing. Now the price of this altcoin has fallen very low, this is the chance for us to buy Ethereum. Stellar's rapid growth, its price is pumping up fast, I believe it will bring more profitable investors. Monero brings privacy to the user, all transactions with this altcoin are completely anonymous. In future Monero will grow and become more popular.