I think the best coin to HODL is still bitcoin ,65% of my money are in bitcoin and the rest on altcoins like ETH and LTC ,gone are the days when you will see 2000% of altcoins ,bullrun has been around for months now and altcoins aren't favouring that much,they will be profitable but not just like 2017 pump
The ICO fever of 2017 has long gone, although IEOs are now looking a bit feverish instead. Yes BTC is the safest bet for a long-term price increase, but I do think there are plenty of good alts out there that will increase strongly as well. It is boring to say it as they are already high cap coins, but ETH and XRP look very good bets for the long-term, too.