As an example, those who mined XSH (Shield Coin) back in November just after its initial launch raked in tens and hundreds of thousands of coins, which they then could sell in December during the boom to the tune of millions.
I guess they have really done their homework before sending their hashes towards mining XSH. The best thing to do is to invest time yourself trying to find potentially good cryptos which will moon in the future. I don't think you ll get a ready made answer here. Just my opinion.
You can start your search at the altcoin ANN section
here