We published open-source, simple and easy to use .NET Standard 2.0 library with some useful utilities.
For example, you can now easily check if email address is temporary / disposable. With string extension methods this can be as easy as following:
bool isTemporary = "firstname.lastname@example.org".IsTemporaryEmail(); //true
Current implementation is offline (known temporary domains are "baked in") and for this reason also very fast.
GitHub repository with examples: https://github.com/AppBeat/AppBeat.Utils
Our official NuGet Package for this library: https://www.nuget.org/packages/AppBeat.Utils.Email/
We plan to upgrade this in future and add some more useful functions.
Please let us know if you have any questions or suggestions.