What do you mean by "communicate an address to receive the gift"? i guess you meant all you had to do is give your wallet address and receive the coins right? To be honest most of those airdrops were just some shitcoins that had a total value of few cents. Again, there were some airdrops were you had to have some certain amount of coin during a certain period of time. Some of those airdrops did have some good price, but as expected the price were dumped (as many users received it and sold it as soon as possible).
Don't waste your time hunting airdrops. They are usually garbage.