What exchanges are US users currently using to trade alts besides binance and bittrex?
Kucoin, Poloniex. There's also Coinbase Pro if you only want to trade about a dozen of the larger altcoins. Huobi also has a US site now (which I haven't tried yet) with a couple dozen altcoin markets.
I think Kucoin is the only option besides Binance that allows unverified accounts.
So now we can clearly see things are not 'goodbye' for our beloved USA traders. Kucoin is not bad but I agree that it has not the charm and huge volume of Binance and CZ. I think this will also serve as an opportunity for Kucoin to step up on their service and they can be the top exchange for USA traders. And like the others said, VPN will always comes in handy.