Another airdrop scam is Telegram bot airdrops of project trading in the market already, you will be told that it is already on coinmarketcap.com and if you want to earn to earn more of the coin that you should donate to an Eth Address
That's a variation of one of the oldest scams in the civilized world--there's a Nigerian prince who is giving his money away to a random person in need (and YOU'VE been selected), but in order to release the funds you need to pay $X in some sort of transaction fee. It's total bullshit and a scam of course, but there are credulous people in the world who live under a rock and who'll fall for it. When a person's greed is activated, they get all sorts of irrational and the end result is losing their dough.
I've never participated in an airdrop, but I've read that a lot of them don't pay at all. I suppose you don't lose anything but your time if that happens, but when they ask you to send them some ETH first? Oh hell no. Stay away from that. That's my suggestion. There are way too many scammers in crypto, and way too many ICOs with the purpose of the coin being some idiotic thing like that Concoin scam (crypto for prison inmates). That piece of
shit crypto will never get used in the real world, outside of morons speculating in it and trying to unload it onto even more gullible morons.