Not really an airdrop, but WCX does does a 50 token signup bonus and a 15% discount on their pre-sale if you're referred by someone. They're aiming to be a big player among exchanges. Ambitious, but their roadmap looks solid enough. Considering investing myself. See https://wcex.co/?ref=VpSUmOgO
Also check out Qoinpro, a web wallet that gives you a miniscule amount of about 15 different coins every day (BTC, DOGE, ETH etc.). Strangely enough it's legit, although it takes a lot of time to gather an amount worth withdrawing. Just something to create and forget for a couple of years, if one of the coins decides to go off it'll be worth it. https://qoinpro.com/b05159e2b5fcba471f379dec18024f35
The way it works (or so they seem) is that they will just get wallet info from the network and check that, no need to send addresses around. Also I thought the social bounties are still not active ....