Below is a non-exhaustive list of exchanges supporting ZCash (as of May 2017):
Allcoin – https://www.allcoin.com
Alcurex – https://alcurex.com
Bitfinex – https://www.bitfinex.com/
Bitlish – https://bitlish.com/
Bitnow – https://bitnow.co.nz/
Bittrex – https://bittrex.com/
Bitsquare – https://bitsquare.io
BTC Alpha – https://btc-alpha.com
BTER – https://bter.com
BX Thailand – https://bx.in.th
Changelly – https://changelly.com/
Coinexchange – https://www.coinexchange.io
coinBR – https://coinbr.net/
Cryptonator – https://www.cryptonator.com/
Cryptopia – https://www.cryptopia.co.nz
Freewallet – https://freewallet.org/
HitBTC – https://hitbtc.com/
Kraken – https://www.kraken.com/
LZF – LZF.com
Poloniex – https://poloniex.com/
ShapeShift – https://shapeshift.io
SZZC – https://szzc.com/
The Rock – https://www.therocktrading.com
TradeSatoshi – https://tradesatoshi.com
TuxExchange – https://tuxexchange.com
USD-X – https://www.usd-x.com
Waterhole – https://waterhole.io/
Yobit – https://yobit.net
Yuanbao – https://yuanbao.com
YUNBI – https://yunbi.com
ZCash community blog 