There are a lot of airdrops going on that give you free tokens for just leaving your email and ethereum address. OMG, Qtum, Stellar and many more were airdropped for free.
The only website I found is
http://airdropalert.com/ and it sucks. Many current airdrops are not being listed.
Does anyone have a better one?You could join Telegram groups that updates people when there are airdrop or you could also try joining bountyhive.io. They also have Airdrops there apart from bounties.