I think there are lots of coins which offer airdrops but the problem how can someone trust their own wallets. I have seen so many wallets having viruses, worms and backdoors. There are some coin airdrops which give in the Ether wallet and waves wallet. So think twice before installing a wallet.
Can you please say some old wallets with viruses, worms or backdoors? I now participating in different airdrops, but never heard about viruses...