please suggest me some best altcoins that can easily give 2x profit if I hold them 1-year.
There are many I guess but only if the market will cooperate. If the market will be more bearish than bullish for the entire year, any good coin cannot even give you that. But assuming that the market will be in its good shape for a year and its performance will also be good, I think you can have the top altcoins. x2 is not that big after all. You can have ETH, XRP, BNB, EOS, XLM, LTC, and other top coins. Even Bitcoin can give you that x2 target.
Long term investment and can give 2x profit in one year I think altcoin have good position in coinmarket and have higher increase volume on exchange market, you can try for investing long term about one year with ETH, XRP, XLM, LTC and BNB coin, I think above coins have potential to be 2x profit with holding one year later.