I'm using the following exchanges.
1. Binance - by far, I think this is best when it comes to security, not to mention the UI/UX is great
2. Huobi - has regular airdrops (weekly)
3. idex - I just use this for trading tokens I get from airdrops  
4. Forkdelta - same with idex, I use it for my airdrop tokens  
5. Kucoin - it's one of the top exchanges now and this has some btc/eth airdrops as well