There are sites like airdropalert.com which post new airdrops as soon as they are available.
But be careful, its time consumimg and projects often just dont pay. I quit taking part in airdrops a few month ago, its just not worth the effort.
That's exactly how I feel about airdrops to... I tried claiming a couple of them a while ago to see what all the fuss was about, but most of those tokens were completely worthless. In the end, I calculated I made less than $2/hour claiming those airdrops...
Off course it's possible I didn't know how to distinguish promising air drops, so I might have spend a lot of time claiming airdrops that would have looked like rubbish for an experienced aidrop-claimer, but still, I think you can better get an IRL job and buy crypto with your income instead of claiming airdrops... Just my opinion tough