There are too many altcoin on cryptocurrency market.So It's so much difficult matter for find good altcoin for buy.Yet I think some altcoin is much better.
1. Ethereum (ETH)
2.  Stratis (STRAT)
3. Litecoin (LTC)
4. Ripple (XRP)
5. Ethereum Classic (ETC)
6. WAVES
7. Monero (XMR)
8. Siacoin (SC)
9. Basic Attention Token (BAT)
10. Populous (PPT)

I hope you get profits in this altcoin If you buy now.