TBF, most of these libraries are not easily discovered. You have to luck on the chance that the library author used similar words as your search query. Barring major stuff (authentication, databases etc), you will rarely know about a library in existence. Search engines are still limited by the language of humans. Unless and until, you note down every possible library you come across for future reference, this problem is here to stay.

Maybe a language having a vast standard library won’t suffer from this problem but it will definitely have other problems.