I will recommend Envion and Tokenpay

I think when I see this now that altcoin development of 2 altcoin that it's possible to develop is the ethereum and litecoin. ethereum currently developing rising rapidly and there is a possibility of the ethereum will persist in its portfolio in addition litecoin also has the same opportunity even though not at the moment but for the coming year and will move as soon as litecoin could probably side by side with the ethereum.
 

If we are talking about the medium term, then my choice is DASH. If we look at the road map, we will see how much has been done this year. Next year we will see a revolutionary platform Evolution, which will simplify crypto-currency transactions and, of course, increase the cost of Dash-coins

And I think that Litecoin have very great prospects

I will speak loudly by calling NXT and XRP coins. because the current NXT has increased dramatically and is very good in the market. you can buy the coin

https://www.viberate.io/ is my favorite non tipicle altcoin atm

I think Ethereum and Litecoin

I completely agree, and want to add that Monero has the more engaged community and broader vision behind it.

I personally will suggest ethereum,  zcash,  and ripple to invest.
1. Ethereum : it's the second largest cryptocurrency. It surely has a great potential and seems giving more in return.
2. Zcash : you can invest in zcash without any risk since it offers privacy,  extra security,  and selective transparency of transactions.
3. Ripple: it's powerful and safer to invest since it's offering instant,  certain  and low-cost international payment.
Whatever you'd like to invest, it's up to you. You'd better think carefully before deciding which altcoins you want to invest,  and don't forget to do some observations.

i will gonna invest ethereum , bitbay both of the coins have alot to offer than the other coins there are some even coins that have nothing to offer and have higher price than bitbay, bitbay is a undervalued coin last month its price is 2 cents and now the price growed 10 times than its original price in a month.

Ethereum, Ripple