Huobi Pro- Verification required, numerous pairs to short, easy registration, low fees
Available at: https://www.huobi.br.com/en-us/topic/invited/?invite_code=rzth3
Poloniex- US based, verification required, leverage -2.5, only a few pairs to short
Available at: https://poloniex.com/marginTrading#btc_eth
Bitfinex- verification required, minimum of $10 000 USD
Available at: https://www.bitfinex.com/
Kraken- verification required
Available at: https://www.kraken.com/en-us
GDAX- verification required
Available at: https://www.gdax.com/
