Can you suggest me which one is best Altcoin coin hold for 2018? 
Ethereum
Litecoin
Neo
Cardano
Iota
EOS
Ripple
This altcoins are my currently hold for long term and I advise you should make a research before invest, don't just make decisions on what do you heard the other people.
These well-known altcoins are always good for long-term investment and they are safe too, but another thing you can do is to invest a portion of your fund into some cheap altcoins, who knows some of these can make x50 or x100 in future.