There's plenty of them, 10$ is already valuable thing for me, you just need take part in every available (avoiding only scam-alike things).
Are you really satisfied with ten dollars? Damn, you are pretty convinced about that.
Most airdrops are not even paying three dollars for a single airdrop, so for me, they are a waste of time
In some countries that is a still nice amount. But there are more valuable airdrops, but we all need to find them.
There are a lot of airdrops, it is hard to keep up, but there are websites where you can keep track of current airdrops.