Mostly some airdrops don't have rank requirement, and you can find it anywhere here in the forum. I think someone created a thread on altcoin discussion about new airdrops so you can check it there. And also, in marketplace(altcoins)-->Bounties, and yeah on Announcement just like everybody said. Sometimes those coin ends up with no value at all, but it's fine though, because it's free! 

Goodluck on finding some good airdrops my friend, I hope you find the best.