There is no true answer to this question because each people could have different opinion and choose different coin. But in my opinion any top coins are gonna be the best candidate as many have said but an underrated nft project that is offering really good product such as mobile game could also bring good return of investment if you choose wisely. If you just want a coin that has good future doesnt matter how much roi you can get as long as its not dumping just choose the top 10 coins or even top 5 coins