Looks like you joined good airdrops because you said that sell a % of the tokens, for me, it's not worth, I've never participated in a good airdrop, all of then I got useless tokens that I can't even sell, it's really sad, Only 1 airdrop was good for me, the Keybase stellar XLM airdrop, all other I've just lost my time with it.
i mostly join those airdrops that links to a exchange. i mean a new exchange that building their own tokens .those airdrops are realy good in my opinion.