from the coins that we know and can predict i say
Litecoin.
it is time for its rise and specially because of bitcoin price rise and also the fact that Litecoin will have segwit soon.
but from coins that are new or unknown, it can be any new coin. they have lots of potential for either a rise or a pump and in both cases we can see 100% rises.
p.s. someone said Doge and made me laugh
It would be difficult for Litecoin to go up 100% in 3 months but it has experienced a long term bear market. A coin that has the highest chance of going up 100% is most likely a new coin or a inactive coin with a pump.
I predict Vcash will go up 100% in 3 months. It is very cheap at 7k satoshi and it will defintely go up to above to 15k satoshi in a pump.