please suggest me some best altcoins that can easily give 2x profit if I hold them 1-year.
IMO when we look for long term investment, it makes more sense to evaluate the market itself. The possibility of an increase in BTC for next year may be about this thought. This increase may be more or less than you say. At least I expect the price will go above $15k. If this increase is sufficient, it will be the most reliable way to try.