I will introduce you a few coin:
1.ETH
2.EOS
3.ADX
4.XVG

Great choices. I also recommend these. I was really dumbfounded looking at the fast rise of ADX in particular. For at least a couple of days just recently, ADX has really come out of nowhere and soar really really high as high as reaching more than 200% increase. That was really awesome of this coin.
For me Ethereum is the altcoins that worth buying, because if you can review the fluctuation of ethereum coin in the market it was increasing trends. Hopefully that this altcoin is continue increasing in cryto currency society.