Golem - It doesn't currently have much use but future use cases are huge.
Monero/ZCash -Both provide great anonymity, if market places accept these coins its game over for Bitcoin
Sia - Might be a flop, might currently be overpriced. But it does have potential, I'm uncertain about this one

Litecoin I've been saying this since my first day on Steemit. Litecoin IS undervalued. It is essentially bitcoin but better for trading and purchasing of goods due to smaller transaction fee. Look at the trade volume, Litecoin will be used in place of bitcoin when bitcoin price gets too high to make transactions worth while. Bitcoin is a store of value, litecoin allows you to exchange value