I have seen some airdrops on Twitter, Telegram, Reddit, Facebook, and Discord, but I don't trust all of them. In fairness, even so, I think that there are many communities on the said social media platforms that are still participating, even if they don't know anything.
Especially on Twitter, Facebook, and Telegram, there are a lot of scammers, so do your due diligence and be careful about the airdrops you enter.