For some time now, Metamask has been making references to an MM token. Given its current valuation of $7 billion, this may be the largest airdrop ever.
It doesn't matter how much the token is valued, even if it's $70 billion, it doesn't mean anything. The value of the Airdrop depends on how much interest the developers are willing to give to the community. Amount for community = amount of airdrop, if they don't want to give anything at all, there will be no airdrop. I don't think MetaMask will give away a generous airdrop. If they're lucky, they'll give away $30-$50 worth of tokens, no more.