ADK has been traded at only aidosmarket (own exchange) before.
But today you can trade ADK at following exchanges.

1.AidosMarket https://aidosmarket.com
2.Nessie https://www.nessie.io/
3.bittrust https://www.bittrust-currency.com/
4.Raisex https://raisex.io/
5.Stocks.Exchange https://www.stocks.exchange/

And some big exchanges are working on ADK listing ( or testing).
6.hitbtc https://hitbtc.com/
7.EXRATES https://exrates.me/dashboard
8.FCoinOfficial / FOne https://www.fcoin.com/fone
9.FatBTC https://www.fatbtc.com/