I think nundervalued Coins are: OPUS (OPT) , Siacoin, Musicoin. But there are so many good projects out there also TenX is what i belive undervalued.
IMHO Monaco is one of the most undervalued, it will most likely reach TenX mkt cap in the next month. They have very similar product and MCO has a better approach to masses than TenX (give MCO as cashback - introducing masses to cryptos automatically)
And so far as my research go, Monaco is trying to be a Visa program managers themselves, while TenX goes for third parties program managers
Waves & Siacoin I also believe will go up quite nicely in the future