Sorry to tell you that I think you are not eligible if you do not have any BTC during the snapshot. The only thing you should do is to pay more attention on bitcointalk alt coin announcement, waiting for next airdrop based on BTC.
This is not really true. Bitcore has another airdrop every monday that you don't need to have any bitcoin to participate. All you need is a bitcore wallet with at least 10 btx in it and you are eligible for the airdrop.
The 1st airdrop is the one where you need to have BTC on a past snapshot date