Even tether is not safe to hold at this point, everythings just spilling over.
Its the safest of course. If it weren't for the fud about tether being scam or to be regulated it should have been the safest. Tether had been existing for years and years, if they were scam the team behind it must have been gone by now just as how bitconnect were. But I don't consider it an altcoin to hold. I guess STK is a good option for now as said above.