I’d say none are safe from a large drop. For example, if crypto starts being regulated it will be hit hard. Also, a large player like Amazon creating a crypto may cause a large drop. There are many risks.
That being said I’m a fan of crypto. I think bitcoin and etherium, as boring as they are, will continue to be safer. But if your goal is safe buy an REIT with a monthly divided or better preferred stock. Stellar Lumens is a google.org project and I’d say is also pretty safe. At this very moment if you have play money then payout coins like NEO would be good. NEO is very low historically so if you buy now and the market recovers you’ll have a good monthly dividend. Selling crypto is never easy so getting a monthly payout makes things a little nicer. Again this is all high risk so do your own research. The market could drop further. So I’d recommend hedging as explained above.